This is one of the most fun stand-up shows in LA for everyone involved - comedians love performing on it, comedy nerds love watching it and regular old drunks looking for a good time enjoy the free beer and license to basically heckle. Don't let the word "Improvised" fool you, this is real stand-up, but instead of doing a prepared set, the comedians must react to suggestions from the audience - either making up completely new material on the spot or reaching back into their memory banks for a shred of an old discarded or retired bit to build from.
The participation and spontenaity make for a really fun atmosphere throughout the whole show, with the comedians often joining the audience to help/torture the rest of the line-up during their sets.
At Rant LA Theater in Hollywood and additional shows throughout the region. StandupOnTheSpot.com for more info.