We have been doing a lot of Improv and working hard at it and I thought I would share some of this info with everyone.
http://en.wikibooks.org/wiki/Improvisational_Acting/Rules
Here is another gem http://www.pantheater.com/Articles/RulesImprovPartI.htm
I like rule number 20 on this one http://www.pantheater.com/Articles/RulesImprovPartII.htm
And last but not least here is a plethora of info
http://improvencyclopedia.org/references/index.html
I hope you enjoy these