The Designated Driver: Offers his services because "I don't really feel like drinking tonight anyways, but I still wanna go out, have some laughs with the boys and scope out some babes." Half an hour into the night he's wishing he hadn't volunteered to be the wheel man as he's left to himself looking like the creepy loner guy in the corner of the party. And why did he have to borrow his parents Suburban so he could bring more people? Although he stays steadfast in his decision to not put the lives of himself and his friends in jeopardy by caving into his wishes and getting hammered, he makes up for this by stealing any DVDs or CDs that are left laying unprotected in the friend of a friend's apartment.
The Best Friend: Will stick by the Designated Driver's side for part of the night telling him "how awesome it is you drove man, thanks a million" which soon evolves into "I don't know how you're staying sober around all these people, man." Eventually, as his drinks take full effect, he'll call the DD a pussy for not drinking and head off into the real party, where he will try to finger a girl he knows the DD has been trying to date.
The Gladiator: Will talk all night about how he's ready to "throw down" with anybody who looks at him the wrong way. He'll get ultra competitive at the beer pong table and antagonize anyone who dares to compete against him, even the cute-girl looking to make her ex jealous. She only signed up because she sorta thought he was cute until he opened up his dumb mouth. Maybe he thought saying "yeah, bitches can blow, but first you gotta blow ME" was a fun little way to simultaneously psyche out his opponent and do a little flirting, but all it did was make her ex pissed and actually want to fight. And we all know The Gladiator doesn't really want to fight, he just wants to talk about how much he wants to.
"Skip Bayless": You think Barry Sanders is the greatest running back of all time? Idiot, everybody knows it's Emmitt Smith. All he wants to do is talk about sports, and by "talk", he means argue. If you'd have said Smith was the best, he'd make the case for Sanders. It doesn't matter which side of the fence he argues on, he's only out to prove how much he knows. When he's exhausted the entire population of the party with his talk about sports, he's got another few hours of material on why 2Pac couldn't hold The Notorious B.I.G.'s jock (or vice versa.)
Martin and Lewis: The team will entertain, and eventually annoy the entire party with their antics. When the party goers grow tired of their slapstick, they will up the ante by playing a game of gay chicken. Beware, because after a few parties, even this gets old, and it's only a matter of time until one of them is giving the other a handjob in the corner while most of the party watches on, first laughing, not being able to believe the level of escalation, and then horrified, realizing what they have been watching. Nevertheless, after the HJ the two will develop a hilarious back-and-forth banter bit debating which one of them is more gay.
The Girl: She's brought along as a back-up plan. At some point in the past she has been in love with, and "done stuff" with practically all of the members of the group (all but the Designated Driver, because she's his cousin).