If families who pray together stay together, then families who act together must contract together, because in Hollywood, not only do individuals get typecast -- sibling sets do, too. Here are some of the best, and some of the worst, of the famous families, and why you should watch out for them.

Alec, Daniel, William and Stephen Baldwin: The Baldwins are the Irish frat brothers of the Hollywood in-crowd. Or not so in-crowd, as the case may currently be. (When did the last good Baldwin movie come out, anyway?) Once I hung with Alec, William and Stephen in a bakery on the Upper West Side. Fine, I served them lemonade and touched Alec's straw after he was done using it. Okay, I still have the straw. But really, Baldwins will be Baldwins. I'll bet Mother B bought hair gel by the ton.

Quintessential Baldwin Movie: Glengarry Glen Ross

Quintessential Baldwin Ex: Kim Basinger

Christian, Kieran, Macaulay, Rory, Shane and Quinn Culkin: I once hung out with Mack, too, at Hitters, Hackers and Hoops. He picked his nose, but was generous with the quarters. The Culkins are a family in transition. Once stalwarts of the crappy-made-for-children genre, Kieran has heralded a new era of indie-Culkin-productions, and Mack and the sibs have joined him for the ride. I'm rooting for the Culkins. I had a crush on Mack when I was nine -- even if he did eat boogers -- and I have a crush on Kieran even as we speak.

Coolest Movie a Culkin has been in: Dangerous Lives of Alter Boys

Family member the Culkins avoid: Evil father Kit Culkin

Ann, Bill, Joan, John and Susie Cusack: It is hard to think of a good John Cusack movie that Joan has not been in. Generally only in his god-awful, stupid, trashy work does he go at it alone. Joan just has more integrity. Everyone loves Joan Cusack. Even Jack Black loves Joan Cusack. The Cusacks are quirky but mainstream, weird looking but attractive, sweet but not cloyingly sweet. Although people say in real life John's a dick. But honestly, who needs real life?

Movie with the most Cusacks: Grosse Pointe Blank

Childhood friend the Cusacks are incessantly loyal to: Jeremy Piven

Jake and Maggie Gyllenhaal: These Harvard-Westlake graduates are lucky, because they're the new hipsters of the Hollywood scene, and they have cool clothes. Whether you're a Gyllenhaalic or not, which you probably are, knowing you, you have to admit that Jake and Maggie are cool. Cool in a way the Cusacks will never quite be -- and John Cusack is cool. They're supercool even though Jake is upset that he wasn't Christian in Moulin Rouge -- cause that's just not cool.

Meta-Sibling Gyllenhaal Movie: Donnie Darko

Maggie's BFF/Jake's GF: Kirsten Dunst

Ashley, Elizabeth and Mary Kate Olsen: The Olsen twins are the mini-wasps of la la land. Elizabeth's their little sister. She's exactly like them, just twinless, so less famous. If they were not famous, Lizzy wouldn't be famous at all, and they would be cheerleaders having sex in the backseat of their boyfriends' chevys. Hell, they're probably having sex in the backseat of their boyfriends' chevys anyway.

Most Sexual Olsen Role to Date: Charlie's Angel's: Full Throttle

Movies Mary Kate has been in without Ashley: ...

Joaquin, Liberty, Rain, River and Summer Phoenix: If families were colleges they would be Oberlin. River Phoenix, may he rest in peace, might have been one of the greatest actors of his generation, had he not snorted himself to death. Or he might have disappeared really quickly. Even though that is doubtful, because he was a good actor, and his pack seems to have made something of themselves. Think Johnny Depp, et al. The rest of the Phoenix clan aren't bad. They're hippies who grew up on a commune, and Joaquin used to date Liv Tyler.

Phoenix Movie That Really is Spectacular: My Own Private Idaho

Saddest Recent Phoenix Fact: Joaquin now comes up #1 when you search them on imdb.com. River is #2.