Remember your 21st birthday? Well, neither will the hedonists in 21 and Over, a comedy sloshing its way to screens March 1. When a straight-A college student and his best friends hit the town to celebrate, the town hits back hard. ''Pretending to be drunk is probably the thing I worked on the most for this character,'' Chon says. ''I did a lot of research at bars .... I don't think I've ever been this committed to a role.''