I passed by the Improv after a day of bicycle messengering.  World-weary woman smoking a cigarette at the door, clearly worked there.  I asked what I had to do to get on stage and do my bit.  

“Singer or comic?” she asked.  

“Matter of opinion,” I said.  

“Comic,” she said. “You don’t get to do your bit.  You get to do two minutes of your bit. Get here by 6, sign the list, wait with fifty others, see if you’re called.  They like you, you can come back and do more of your bit.”  

Never took her up on it, but I liked her style very much.