Revisiting his impetus to write his first feature, Jon Favreau told the Web site Grantland.com that he didn’t even realize he was writing a movie. “I couldn’t wait to share it with my friends more as, like, doodles in the notebook than saying, ‘Hey, here’s my big movie.’” Favreau was a young, workaday actor in Hollywood when he turned out the screenplay for Swingers in about a week and a half, he said. The roman-a-clef has him as Mike, a young actor-comic living in a crummy apartment, new to Hollywood and heartsick for an ex-girlfriend back home. He is the voice of reason, and doom, in a gaggle of young striver-operators who affect a Rat Pack cool and mostly fail at it. They’re so money. Swingers stands as an early showcase of Vince Vaughn’s comedy chops. He plays Trey, the friend constantly bucking up Mike with hipster positivity and total BS.