My "day job" is playing in indie bands and I tend to think of myself as a visitor from the distant Galaxy Of ROCK, so when I made my first visit to Planet Comedy four years ago I was aghast at the very idea of previews. I was horrified to see people standing in front of audience reading jokes off pieces of paper, being quite blatant about the fact that they not only hadn't learned it, but weren't even sure if it was any good. I was further appalled to discover that this wasn't even something to be ashamed of - whole evenings were dedicated to previewing material, and audiences seemed to love it!
You'd never get away with that in the Galaxy Of ROCK. Sometimes bands will play songs they don't know very well, but they'd at least have the good grace to be apologetic about it, and would probably follow it up with an old song they did know. Even then they'd at least know where the chorus went and when it was time to stop. In fact, the closest bands get to preview type shows is when they say "We're going to jam a song for you know" which is, of course, the signal for the entire audience to flee into the bar.
I have to admit though that it does sort of work. Gags that seemed hilarious when they popped into my brain on the tube can turn out to be rather less amusing when said out loud in front of an audience, and I've often had to drop whole chunks of script that seemed the very height of wit when I sat at home writing them but are, in actual fact, boring.
The best part of it's when jokes appear completely by accident. Just before doing a show in Lewisham the other week we agreed to drop an entire scene, and the fact that we had to leap over the resulting gap led to the biggest laugh of the whole thing. We kept that bit in!
Still, I'm worried about how this'll affect me when I go back to playing with the band. If you seem me later on this year playing an entire gig from a sheet of paper, occasionally stopping mid-song and saying "That doesn't work - here's something I thought of on the bus" then you'll know I've finally gone native!