I dunno, Pong? Maybe something on the vextrex?
Can you people seriously remember the first time you played a videogame??
I don't actually remember my first time playing video games. I do however remember my brother only allowing me to play a very small number of his games, so I can reason out which ones I would have played first. Even still it's only a guess though. I think most of us just know the situations in which we would have been playing games and can therefore figure out which games we would have played first.
Some people were older when they first played a game though so they probably do remember.