MECC made I several versions of Oregon Trail, the last one for one of the later revisions of the II (or maybe it was an early Macintosh) had the best hunting minigame. You could mow down the entire animal kingdom with rapid fire. Of all of their games though, I ended up playing DinoPark Tycoon the most, but by then I was playing at home. It was a fantastic game and birthed a huge strategy genre. I had a pirated copy of Carmen Sandiego and could never quite figure out how to play or make it fun.
Descent was so good. I didn't play a ton of it but I ended up playing its N64 clone Forsaken for many hours. Mechwarrior 2 was the first real 3D game I got into. I can remember being amazed at its limited and low resolution texturing.