Speaking as someone who worked 14 straight retail Christmases: Bad Santa is a necessary holiday tradition, the flip side to the goodness of A Charlie Brown Christmas and It's a Wonderful Life. Terry Zwigoff's tinsel-choked caper comedy is about the side of Christmas that retail employees see—a flood of hideous people at their greediest and most wretched, clawing desperately for their own interests at the expense of everyone else. Billy Bob Thornton's performance taps into something raw: For 90 minutes, he is the anti–Christ child. In other words, he is America at Christmas. (Grand Illusion, 1403 NE 50th St, 523-3935, 11 pm, by donation)