My first gaming memories, period. When I was a kid, we didn't own any game consoles, but we did have my dad's Windows 95 computer. I got a GameBoy much, much later, and consoles even later than that.
I played the shit out of all of the Humongous Entertainment games that I could get my hands on, playing them over and over, and the semi-randomized nature of their later games made that remain fun for a long time.
I also had a few of the Math Blaster and Reading Blaster games and I liked those too, but not quite as much.
Eventually I started playing the ClueFinders series, and I loved the puzzles in those. I did play them while below the recommended ages though (I remember playing the "5th Grade" and "6th Grade" games when I was still in the 4th Grade).
Wow, all of my earliest games were educational games. Huh.