We have very good quality (relatively) visual projectors at both Noisebridge and Sudoroom

However, I'm wondering if I should invest in a cheapie projector because that would give me more mobility. Then I could projection map at skateparks, he omni commons, and have more than one projector projecting around a large room. 

This wouldn't be quite the equipment I need to recreate something as crazy as the Van Gogh limestone exhibits in France (there's one in SF right now too) but something truly fun would be a lot of little projectors!

What are some good starting off points and open source projects around projection mapping?