Radio Shack is selling a Hummer racing game that's based on Jeri Ellsworth's C64-on-a-chip design.
A number of people have spent the past few months figuring out how to turn the Radio Shack game into a full-blown C64. There is a FAQ available.
One cool thing about these is that it's very easy to add a PS/2 keyboard to them. Having a C-64 with an IBM Model M keyboard sure sounds nice...
I also found a forum dedicated to this and other Commodore-related topics.
Ah, memories...