Fill My Room!
Okay… this is one I should have thought of — FillMyRoom.com will put a 2×4 LEGO brick in their room for each $1 donated, with special on-line advertisements to those who donate $10 or more…. I wonder if he has change for a 2×6.
UPDATE: The web-site has changed and I don’t think it’s related to filling a room with LEGO any more. And the image I found off to the side is just a typical AFOL’s LEGO room. 🙂