Courtesy of Lifehacker, thought Sallie and her boys might be interested in this one. Could probably find some "educational" games to play on here as well... maybe not :).
Tom - Do you have a RaspPi?? My guys are currently working on using it to play sounds when someone walks between two infrared sensors (think musical stairs at St. John's). Fun stuff!
Concurrently they are dabbling with an Arduino to run a DIY 3D printer they are building.
I'm in over my head here!