If yours didn't have cartridges, it was probably one of the more standard home models that had 'built in' games. My family had an Odyssey 300 (similarly, I don't know who bought it or how it arrived). It featured tennis (aka pong), smash (aka squash or wallball), and hockey with 3 difficulty levels and two paddle wheels built into the console. Does this look familiar? http://en.wikipedia.org/wiki/Magnavox_Odyssey_series#Odyssey...