Kathy Sierra talks about an Ultra-Rapid-Design Party with some great brainstorming tips that I'm going to shamelessly steal for my Idea Markets and Innovation Retreats.  Here's how she describes it:

Forget focus groups. Forget endless meetings and brainstormingsessions. Throw an ultra-rapid-design party, and do it in a single day.This approach exploits the wisdom-of-crowds through a process ofenforced idea diversity and voting, so no consensus, committee, or evenagreement is needed. And it's way more fun.

The Product Design Dinner Party takes 9 people, a pile of diverse"inputs", and has each of the 9 people voting on--and pitching--oneanother's ideas to continuously reconfigured groups of 3 people,letting the best ideas rise to the top. The process is a littlecomplicated, but it's derived/modified from an existingrapid-prototyping design I'll talk about later in the post.

Go to the post for a step-by-step guide.  Definitely worth a try.