Inspired by tinyE's comment on a different thread.
The first game I ever played was a very simple game called Red Baron. It was two dimensional and almost pointless, but my brothers and I still had tons of fun playing it.
EDIT: Actually the game was called Sopwith. My mistake. :D
My god, I wondered what that side-scrolling shooter was called. I assumed it was "Red Baron" as well. Long time ago. That was one of my first as well. The A.I. planes would always do the same moves, and always go on the same suicide missions against your base.
There were many ancient IBM PC-XT games I played as a small child. Moon Bugs
was one I remember playing a lot of, as well as "infotainment" titles from Scholastic Software like Agent USA
(which did teach me U.S. state capitals and major cities) and another one, Journey to the North Pole
And one other early 80s IBM PC game that I can't for the life of me remember the title of, but I played a ton of, took place in a "Mad Max" styled post-apocalyptic wasteland. You controlled a fighter plane and your job on each world-map stage was to destroy all of they enemy motorcycles, planes, and trucks. Each successive level there were more and more of them and more numerous. You'd run up flush against one on the world-map and then go to a "combat map" that showed your attitude on the top map and altitude on the bottom. Trucks were always a bitch because you could only destroy them with a shot in the tires and you ran the risk of crashing into a hill when trying to do so. I remember on the world-map that you had certain refueling depots (I think) and clusters of enemy planes had a tendency to camp out on them so you were forced to fight them if you needed to revisit 'em. Damn, I wish I knew what that game was.