I challenge you to check out the LEGO NXT pinball machine and not want to play it. Pinball is always a good and affordable time, and LEGOs are God's gift to man. Combine the two and you are guaranteed a great outcome.
The LEGO NXT pinball machine was built with over 8,000 LEGO pieces. According to its site, the pinball machine is run by 6 NXT robots, 9 touch sensors, 10 light sensors and 4 motors. Watch the LEGO pinball machine in action above. I guarantee awesomeness.