If you are looking to have a bit more fun with your Arduino why not use it to launch some model rockets! That is what the guys from  NortHACKton did. They have a full schematic available on their site.

Thanks Martin.

“It’s a very simple little board, consisting of a driver chip and a relay and the connection to the dot matrix display. I chose to use the ULN2003 to switch the relay primarily because the package already contains a freewheeling diode and can be directly driven from the arduino and secondly because I have 3 tubes of them in the shed already due to a misorder on a previous project.”