LumaFix64: Commodore 64 with less stripes
biosrhythm.com
biosrhythm.com
In addition, 6510 assembly is pretty straightforward getting into, so writing your own software to make use of the hardware you just designed and built is not unsurmountable for a hobbyist.
Heck, I still play with my C64 on occasion.
With his USER and EXPANSION ports, the Commodore 64 was designed from the ground up to be expandable, and to be used as a controller, either in industrial applications (controlling traffic lights, for example), or as a complete house systems controller.
Writing code on these machines is still a very rewarding activity. Maybe not financially, but certainly the fun of actually doing something that was once considered impossible on these machines, is just really, really fun.
Myself, I'm an Oric-1/Atmos fan. http://oric.org/ has an absolutely astonishing amount of software for the machines, which barely made a ping in the 8-bit wars, and the fine folks at http://defence-force.org/ continue to bring new titles to the platform. More fun to be had with an old computer now than ever before .. after all, old computers never die. The users do!
Sorry, couldn't restrain myself.