(BENEFIT) A communist costume contest ("everybody wins")! Pictures with Fidel Castro! Songs by someone named Chi-Chi Guevara! Slap dancing! In case you've been living under a socialist rock: A slap dance involves people dancing around and slapping the shit out of each other. It is obviously the best thing in the world. This is a benefit for Washington Ensemble Theatre, whose members will probably be in a celebrating mood after this year's Genius Awards. (Havana, 1010 E Pike St, www.washingtonensemble.org. $10 with costume/$13 without, 8 pm, 21+.)