OMG!! Best. Resource. Ever.
Go here: http://www.humanpingpongball.com/
And you’ll find this:
Improv Encyclopedia Home Page
Welcome to the Improv Encyclopedia! Here you will find tons of stuff related to improvisation theatre. Look for improv games, handles, concentration exercises, drama techniques, character exercises, warm-ups, long form Improv formats, improvised show formats, tips for improv workshops and much more.
Check out the games, which are even viewable in categories, glossary, references, music and you can download the complete current set of games as a pdf (about 500 pgs).