In a school where the three reigning popular girls — each hoping to become prom queen — are like “warlords” operating under an uneasy truce, the latest, hippest weapon for dominance is the G.B.F.: the gay best friend. Problem is, North Gate High doesn’t have any “’mo’s”… or does it? When geeky Tanner (Michael J. Willett), who’s not very fabulous (he’s into comic books) is accidentally outed, he becomes a pawn in the games of Fawcett (Sasha Pieterse), ’Shley (Andrea Bowen), and Caprice (Xosha Roquemore: Precious: Based on the Novel Push by Sapphire). (Harry Potter’s Evanna Lynch, aka Luna Lovegood, appears here too.) Will he tolerate being a fashion accessory for the sake of popularity? Writer George Northy and director Darren Stein aren’t afraid to go for broad farce here, and it’s the sharp satire cutting through the sweet silliness that makes this a refreshing change of pace for teen comedies. The oppression of peer pressure — including the kind that involves religious cliquery — earns a well-deserved thump, as do the diminishing stereotypes that reduce wonderfully weird, idiosyncratic individuals to less than they deserve to be seen as. G.B.F. probably doesn’t have anything new to say to anyone who’s finished high school, but almost anyone still stuck there may find succor and amusement here.