My Remote Controlled Bumper Cars. Controlled by driving stations using NXTs and HiTechnic IR Link Sensors. Fully lighted for nighttime play, the bumper cars are using the RC unit from the 8183 RC Racer set. 12 IR Link Sensors line the top of the tower. The version shown here was displayed at Brickworld 2009 in Chicago, working on putting a roof on it for Brickfair in August 2009.
Base is 60 inches by 45 inches (3 x 4 x-large base plates). Track is simple SNOT building, about 8000 bricks in total for track, sides and tower, plus a ton of rubber bumpers.