Railroad steam engine. Though I may not need to run it anymore. So it will be in my living room.
T Rex skeleton, so I can put a santa hat on it during Christmas. Or an animatronics one, cheaper and I can run it around my living room.
Air pinball tournament at Expo. 10 people lined up. Playing air pinball for two minutes, with numbers on their backs. Audience votes for best one. Winner gets $100,000.
LTG : )