24-Hour Party People, on BroadwayAt The 24-Hour Plays Monday night, a starry group of actors, playwrights, and other show people — Jennifer Aniston, David Cross, Adam Rapp, Elizabeth Berkeley, Wallace Shawn — got together to write, direct, rehearse, and perform six plays in just one day’s time. It was a benefit for Working Playground, which brings arts programs to underserved New York City schools, and in addition to raising money, it gave its audience a night of unpolished but riveting entertainment. Some highlights …