Donkey Kong - but I was terrible at it
Space Invaders
Pac Man
Dig Dug
Moon Patrol
Chopper Command (used to play this for hours on my neighbor's Atari 2600)

You can play some flash versions here:

You can also download and play a number of old games from:
Atari Mania

I still play them on my M.A.M.E. cabinet:

Farewell - June 4, 2020