Graduated HS in 75, ditto on never seeing one in school. However, one of my buddies older brother was an electronics hobbyist and he built an IMSAI that we got to play with. The keyboard was scary, a board with delicate little stubs for each key. Storage was cassette tape, which was slow as hell. However, the brother had an account at UC (Cincinnati) and an acoustic coupler modem (150 baud). We played the original Adventure over that crappy hardware and I don't think I ever had so much fun. I can still remember the time, in total frustration, I attacked a dragon and responded "yes" to the question "with your bare hands?". I got the response "Congratulations! You have just vanquished a dragon with your bare hands! (Unbelievable, isn't it?)". I was basically hooked at that point.
First real programming experience was my junior year of college, running PL/C on cards on an Amdahl at Ohio State. Now *that* was quite an experience. Each program cost money to run, and you got a certain amount at the beginning of the quarter to do you work. Had to beg the TA if you ran out. Waiting at 2am for your job to come through. PL/C would "fix" your compiler errors, generating errors for code you never wrote!
God I'm old. Oh yeah, get off my lawn