Pong for me, but not actual pong. Rather one of those early 80's pong knockoff consoles. Who knows which. Something along these lines:
Some of my dad friends had one that I'd play when we went to their house, and then we got a (barely) different one. No wonder Atari 2600 and eventually NES were so mindblowing.
edit: Wait it could be Donkey Kong Country... I have home video from I think 1994 when I was almost 3 years old, watching my brother and cousins play it. Probably mario still, but I don't remember.