Seven Deadly Sins:

Origin: The Catholic Church separated sins into minor "venial" ones, and the seven "mortal" sins of Lust, Gluttony, Greed, Sloth, Wrath, Envy, and Pride.

Why it makes sense: Because everyone likes to let themselves go sometimes, and vice is far easier to attain than virtue.

Decorations: The natural squalor of your life should provide a ready-made backdrop. Pile dishes in the sink, throw your dirty clothing around the house, flip some of the furniture over, and make sure only half of the light bulbs are working. Play episodes of the Sally Jessy Raphael show on mute.

Food: Pot brownies, Mallomars, Cheetos, birthday cake, oysters, dark chocolate.

Drink: Jell-O shots made with Everclear, keg beer, absinthe.

Dress: It's not what you wear, it's how you behave (or don't).

Music: The Eurythmics, Missy Elliott, the Doors, Fiona Apple, OutKast, Nas, Ricky Martin.

Quincea¤era:

Origin: The Hispanic-Catholic equivalent of a Bat Mitzvah, this traditional religious ceremony and party is a celebration of entering womanhood at age 15.

Why it makes sense: This is your Disney dream realized. Boys get to be princesses, and girls experience the thrill of wearing a white gown without needing a groom.

Decorations: Crˆpe paper streamers, beads, dozens of those candles that come in jars with the religious paintings on the outside ($1.59/ea); go to Supreme Supermarket at 43rd and Walnut for all of the above and for an incredible supply of Cuban, Peruvian, Mexican and Argentinian food.

Dress: Old prom dresses (for both sexes), tiaras, jewelry from Pretty Pretty Princess, fishnets, ill-fitting suits with shoulder pads, big hair.

Food: A cake with a Barbie-doll topper, flan, guacamole, carne asada, Fla-Vor-Ice.

Drink: Margaritas, kamikazes, cerveza.

Music: Wyclef Jean, Fat Joe, Shakira, Sublime, Rolling Stones, Pavement, Selena.

Valloween:

Origin: The lustful, costume-loving (and naturally, exciting in the bedroom!) bastard child of Halloween and Valentine's Day.

Why it makes sense: All of the sex appeal of Valentine's Day with none of the sentiment; all of the treats of Halloween with none of the tricks. Love is death, anyway.

Decorations: Skeletons, bones, black hearts, pink skulls, candles.

Dress: Dress as your favorite victim of love or evildoer. Examples are Sid and Nancy, Heathcliff, Satan, Jackie Kennedy, Johnny Cash, Dracula. Fake blood should be used liberally.

Food: None. Boycott commercial holiday products!

Drink: Straight-up gin served in a champagne flute with a razor blade at the bottom as garnish. If this seems too extreme, go for rum and Coke, dry martinis, and Johnnie Walker Red. Absolutely nothing pink or girly.

Music: Joy Division, the Sex Pistols, Elvis, Television, Lou Reed, Smokey Robinson and the Miracles, Arcade Fire, Dolly Parton, Jeff Buckley.

Doppelg„nger:

Origin: A doppelg„nger is the ghostly double of a living person, an "evil twin." Doppelg„ngers are regarded as harbingers of bad fortune. Seen by a person's family or friends, a doppelg„nger foretells illness or danger, while seeing one's own doppelg„nger is an omen of death.

Why it makes sense: Because we go to Penn.

Decorations: Mirrors, spoons, crystal balls, and lots of opium (if scarce, substitute incense).

Dress: Dress identically with a friend, or trade identities with a friend. Or steal someone else's identity and freak them out when you show up looking like them. Or dress like Percy Bysshe Shelley. Don't dress like Mary-Kate or Ashley.

Food: Cherries, cheese, walnuts, pomegranates.

Drink: German beer, peppermint schnapps, wine, double shots.

Music: The Everly Brothers, the Breeders, the Bee Gees, Aphex Twin, t.A.T.u., the White Stripes.