On the spur of the moment

I want to throw an improvisation party. Get a load of people together, with snacks, food and drinks. Treat it like a normal gathering but throw in an improv game every half hour or so. I think some of my minions, er friends, would react interestingly to this situation. If it went particularly well take it onto the street and start involving random strangers or staging fights or otherwise being a menace to the community at large.