I first programmed a computer in 1977, when my best bud got a TRS-80. We had an enormous amount of fun doing this, and I owe a lot of what I do now to those days. We used the thing pretty much every day until around 1980, when he spilled a glass of orange juice on the keyboard, which is where the CPU and everything else lived.
A really neat simulator of the TRS-80 is available on the web, running as a Java Applet. So, essentially, a web page today can be what a computer was 30 years ago. You can enter and run programs in the window, which looks just like the screen of the TRS-80. I immediately wrote and ran a couple of programs I recall writing back then. It was weird, like seeing my own life simulated on a computer. Or like stepping out of a time machine. As non-descript as the TRS-80 was, it occupied a lot of mental and emotional real estate when I was 13.
One kind of funny point- the simulation runs considerably faster than the original computer did.