I think I still have the Odyssey. Know I still have the Odyssey II. Learned how to add and subtract because of some blasted math-based drag racing game on the Odyssey II.
Quick fact, the original Odyssey was more like a Pong based system or, as something you young whippersnappers will be more familiar with, a Plug'n Play TV game. Everything was technicaly one built assembly, no game carts, non-removeable controllers, non-removeable antenna (aka RF) cable. Only part that was a seperate piece was the AC adaptor.
Odyssey II took most everything to the next level but Magnavox still failed to guage the need for removeable joystick controllers, as they were once again pre-wired into the console. Odyssey II paved the way for RPG's to come to consoles though as at least one game maker made a hybrid video game-table top RPG, which at the moment I'm thinking was named Rings of Power, or something like that. Later on the Mattel Aquarius would get a couple of similar RPG games released for it, but as that system was nothing short of being a major league failure no one really noticed them.