The first real programming I did was writing games and mods for the Color64 BBS I ran when I was about 12. It was actually an interesting and modern design, I now realize...its main loop was in assembly while the apps and forum and other stuff was in BASIC, making it, effectively, a scriptable system (live scriptable, even, since you could change things on the running system). It was also a somewhat multi-user system, in that a sysop could interact with users while they were on the system. The reason it wasn't all written in BASIC was that BASIC wasn't fast enough to serve a 2400 baud connection (I believe disk routines also had some reason for being in assembly, as well), much less the 38,400 modems supported by Swiftlink.

That old C64, and the BBS culture, shaped me and my life profoundly. I should probably send Greg Pfountz (the author of Color64) a nice thank you email, if I can figure out how to reach him.

The source and manual for Color64 were released years ago, and the manual is an interesting read in terms of understanding the architecture and seeing how advanced a system could be on such a tiny machine.