"Open Mic Night" Not Really Open

So I wandered into The Dregs coffee house yesterday and there was a sign on the door for "Open Mic Night tonight. Music and Performance Art." Naturally, I went back that night. By the time I figured out what was going on, about 15 people had signed up ahead of me, so I waited and watched all of these very angry women play guitar and sing about all of their failed relationships. The scene was not what I would call cheery (and it was easy to see why their relationships failed) but I felt it was a good vibe for the Blues Danse. When my turn finally came up, I decided to do an a capella danse number - no music. Since it seemed like each of the other performers sang three songs at about five minutes apiece, I selected a routine that was 15 - 20 minutes in length. First, a few in the audience kept clapping during the natural pauses in the routine. Then, after only ten minutes the dude who introduces everyone tried to interrupt my number by telling me, "time's up, let's wrap it up." Finally, one of the pissed-off chicks came up and pushed me off the stage. It was incredibly rude, but suddenly everyone was clapping loudly and cheering, so I guess they liked me. I might go back there next Thursday night.