It's barely 11:35 p.m. when the first freshman of the night starts throwing up in the women's bathroom.

"Do you realize it's 12 o'clock and we haven't been to one party yet?" Ashley asks her posse of drunken female friends before sitting woozily on one of the available chairs towards the back of the room. She's wearing a tight black tank-top, jeans and has a red and blue Penn tattoo -- presumably fake -- on one of her shoulders.

"We need to get some bread into you," one of her friend's says. A few moments later, a gaggle of girls is following Ashley into the bathroom. Her retching begins before the door closes.

"I can't believe this is our pre-game," one of the freshman girls still outside of the bathroom says, tiny and visibly drunk, with long hair and a few beaded necklaces. Phil Collins' "I Can't Stop Loving You," plays in the background. When Ashley emerges, the girls crowd around her, fighting to force-feed her cookies and water.

I go into the bathroom right after Ashley. By the time I get out, she and her friends have disappeared.

In University City, two worlds move around each other -- the students and the locals -- and the two rarely cross paths. In order to watch both, I spent a Saturday night at the McDonald's on 40th and Walnut streets, from 10:30 p.m. to 7:15 a.m., and this is the story of what I saw.

It's barely 11:35 p.m. when the first freshman of the night starts throwing up in the women's bathroom.

"Do you realize it's 12 o'clock and we haven't been to one party yet?" Ashley asks her posse of drunken female friends before sitting woozily on one of the available chairs towards the back of the room. She's wearing a tight black tank-top, jeans and has a red and blue Penn tattoo -- presumably fake -- on one of her shoulders.

"We need to get some bread into you," one of her friend's says. A few moments later, a gaggle of girls is following Ashley into the bathroom. Her retching begins before the door closes.

"I can't believe this is our pre-game," one of the freshman girls still outside of the bathroom says, tiny and visibly drunk, with long hair and a few beaded necklaces. Phil Collins "I Can't Stop Loving You," plays in the background. When Ashley emerges, the girls crowd around her, fighting to force-feed her cookies and water.

I go into the bathroom right after Ashley. By the time I get out, she and her friends have disappeared.

In University City, two worlds move around each other -- the students and the locals -- and the two rarely cross paths. In order to watch both, I spent a Saturday night at the McDonald's on 40th and Walnut streets, from 10:30 p.m. to 7:15 a.m., and this is the story of what I saw.

**

At 10:50 p.m., I am the only white person in McDonald's. The place is busy, but not crowded. A man orders a large milkshake. As the cashier takes his money, the milkshake starts overflowing behind her. She gives him the drink and continues taking orders for a few minutes before wiping up the spill. There are some pairs of men sitting at tables, but mainly the place is full of high school kids. In one corner, a couple sits together. The two are about 15: he's wearing a black doorag, and she's talking into a phone covered with silver rhinestones. At another table, there is a revolving group of teens, new ones constantly coming in, ordering food and taking the seats of counterparts who have recently departed.

I watch as one of the workers -- a heavyset, middle-aged woman with a small afro -- carefully makes her way around the restaurant, keeping the tables and floors clean, emptying garbage cans, wiping up messes. Over the course of the night, she is the only McDonald's employee who expresses an interest in my presence (other than one of the cashiers who will, at 5 a.m., when one of my friends and I are alone for the second of two 15-minute periods, yell to his co-workers, "Yo, tell people we're closed," even though McDonald's is a 24-hour establishment).

"How many years you have to take classes?" she asks. At first I misunderstand her, so she repeats herself.

"Four," I answer.

"That's not too bad," she says. I agree. I ask her what the busiest hour of the night is.

"I don't know," she answers, "but I know the busiest days are Fridays and Saturdays." I find out she's been working here for three years, always at night. As the hours pass, she loses interest in me, but she's always working, on her feet for her entire shift. She is kind; unobtrusive, but quietly smiling at the diners around her, occasionally cracking a joke with a customer.

By midnight, the crowd is almost completely different. The soundtrack marches forward -- some woman sings a cover of "You've Got a Friend," Cat Stevens' "Oh Very Young" comes on, Otis Redding's "Sitting on the Dock of the Bay," Dawson's Creek's theme song "I Don't Want to Wait" -- while more and more groups of drunken students fill the restaurant. At this point the crowd is still mostly underclassmen -- "It's across the street from the Freshgrocer," one girl says into her phone. "It's on, umm," and she walks outside to check the street number. People age slightly as the hours pass. A boy in a suit holds up a pack of cigarettes.

"I bought these yesterday. There were 20 of them, and now there are zero," he says, sounding almost excited. "I gave 13 of them away." He takes out a Zippo and starts playing with it. One of the guys he is with, a kid in a white, button down shirt, khaki shorts and New Balances, says a little later, "It's the Jewniversity of Pennsylasia," trying to illustrate some point.

At 1:40 a.m., a well dressed man with distinguished looking white hair buys a sandwich and tosses his bag carelessly on the ground, then heads outside and sits on one of the benches to eat it.

Fifty minutes later I stand in line, waiting to order my second large Diet Coke of the night. (The 32-ouncer -- my second of four -- is no longer dwarfed by the formerly offered 42-ounce behemoth.) Everyone has a story about this McDonald's, many revolving around the low quality of service, but I only wait four minutes for my drink. Right in front of me, a kid I remember from my freshman dorm stands with a friend, picking up a huge order of food. Two guys he knows come up behind him, one grabbing his butt.

"You guys must be high," the butt-grabber says, looking at the bag of food.

"We've definitely been smoking marijuana," the kid I recognize says. "Definitely been smoking." The cashier and I share a smile.

***

A sign on the wall reads, "This is a non-soliciting establishment," but over the course of the night, panhandlers come in continually, often walking in, and out, and in again hours later.

Early on, a man in a white Nike hat, carrying a blue backpack, sits alone at a table.

"Sorry," he says quietly to the people next to him, or whomever passes by. "Do you have anything to help me out?" For the most part, people ignore him. Periodically, a man in a bright orange jacket who had been sleeping for a while at one of the tables outside the McDonald's front walks around inside, carrying a large, rolled cigarette in one hand. He doesn't light it, just carries it in front of him, a can tied to his clothing. At around 1:30 a.m. he is kicked out as he stands by the bathroom, waving his cigarette and talking to himself.

About an hour later, one guy who has been wandering in and out all night walks in carrying a large doll in a purple box. He is wearing a dirty suit jacket with an open shirt underneath.

"This is an American Sweetheart Doll," he says, walking from table to table, holding it in front of him. Nobody offers to buy it.

At 3:55 a.m. the menu items switch to breakfast.

"Does it calm down for good now?" I ask the woman who has been cleaning all night.

"I don't know," she says. "It's kind of weird on the weekends. They come, they go."

The place starts to empty out. At some moments, it's just my table and another one or two. When another man comes in asking for money, he walks towards the only other taken table in the place, currently occupied by two men and a woman, all in their early twenties.

"Do you have any change?" he asks, his voice low.

"You're just going to spend it all on drugs?" one of the seated men asks him. "You do drugs?"

The panhandler looks down, as if considering answers.

"Yeah," he says finally, sheepishly. The other seated guy, wearing a red baseball cap, looks at him.

"You do drugs?" the guy in the hat says, taunting him. "I do drugs every night. Drugs, drugs, drugs." The standing man looks around and then walks out. The table bursts into raucous laughter.

"Only you could scare a homeless guy away," the first man says to his friend in the red hat. The girl agrees. A couple of seconds later, red hat starts taunting one of the McDonald's cashiers who is taking a break sitting at a booth across the aisle from them. The girl, apparently his girlfriend, keeps apologizing for him, as he mouths off about how the cashier isn't really working.

"Just don't answer him," the girlfriend keeps saying, trying to shepherd her compatriots out. "Just don't answer him. It will end things."

Finally, they leave.

***

From 4:30 a.m. on, it's pretty quiet straight until morning. One old man comes in singing and buys a small cup of coffee. As he leaves through the side exit on 40th Street, he trips a little while smiling at my friend.

"I'm sorry," he says, his whole demeanor warm. "I was laughing at you." As he leaves, the McDonald's employee who had been harassed by the customer minutes before, sits at her table enjoying her cheeseburger. Another woman, still behind the counter, pulls out a granola bar.

After the cashier finishes her cheeseburger, she starts dancing around.

"All I want to do is just kick off my shoes and relax my feet," she says. She goes to the front of the restaurant, where a row of stool-like chairs is set up in front of a counter. She lies on one of them.

"You're lucky people's dirty butts have been on these seats, or I'd put my head down on them. We should have bunk beds in the back."

She stands up and goes back to the middle of the restaurant where, now almost alone with her co-workers, she keeps talking.

"I'm a one-woman woman. If she ain't got no titties and no pussy, I don't want you," she says, to no one in particular. "I'm trying to go home, maybe try and catch another episode of Room Raiders, maybe they'll be some babes there." She claims that, watching an episode of the show recently, she could predict which girl one of the contestants would choose.

At 5:30 a.m., an employee sits at a booth, taking a break. By 5:40 a.m., he's asleep. He wakes up for a minute at 5:49 a.m., coughs a few times, and then puts his head back down. At 5:58 a.m., a man wearing a white, button down shirt -- apparently the "big manager," usually absent but there for the night -- wakes him up.

***

Suddenly, at 6 a.m., things start to pick up again. After over an hour of quiet, there are small groups trickling in. At 6:15 a.m., two pairs of men come in separately. They stand around by the counter. One pair consists of an extremely tall, thin young guy and a much shorter, heftier man. One member of the other pair is wearing a large gold necklace.

Right in front of the counter, there is a quick transaction. The tall kid gives the guy, wearing a black tank-top, some cash, and the guy gives him a bag of what looks like pot.

"Smell this shit," the seller says. The two groups don't talk anymore, just split apart, waiting for their orders. A woman stands, swaying for 15 minutes in front of the counter, before some guy comes off the street and leads her out. The really tall guy and his friend get into a fight with the cashier about their order. It goes on for a few minutes, and then the cashier gives them hash browns to appease them. They walk away.

Even though it's a Sunday, there are still people going to work. As my friend says, you can tell who's starting the day and who's ending it, by how red their eyes are. Some people come in wearing Allied Security uniforms or suits, while others stagger around, looking sick, and tired, and sometimes dirty.

Before I leave, I order an egg and cheese biscuit, which I scarf down quickly. I haven't seen any Penn students for hours, but now you can see some outside, walking home after a night in someone else's bed, or wearing pinnies, preparing for some early morning race. None of them comes into McDonald's.

In eight hours, I have seen few interactions between the two groups of customers who both come here jonesing for fried food and company, and maybe more on their Saturday nights. They swerve around each other, buying the same things and using the same restrooms, but rarely sharing more than space.

At 7:15 a.m., I stagger outside. I am exhausted. Some of the workers from the night have gone home, but most are still there. The fresh air feels good.