Keyrah lets you turn a C-64 keyboard into a USB keyboard that'll work with a PC. So I could take a C-64, remove everything from the casing but the keyboard itself, install this board, and then use the keyboard to run a system like El-Hazard. Heck, add some dummy cabling to make it look as if you're actually using a C-64. That'd be pretty funny.
Then there's Zoomfloppy which lets you connect your C-1541 to the serial port on your PC. What this does is to enable you to back up your old C-64 disks (assuming any are still any good) to the PC, where you can use the disk images in C-64 emulators. It's $35 and I think I need one of these. My entire collection of C-64 floppies would probably fit on one CD-ROM too, assuming they're all readable. (Which I fervently hope they are--at least the word processing data disks.)
This is the page with all the information on Zoomfloppy archived here for future reference.
Looked downstairs, briefly, for the 1541 that I permanently converted into Drive 9 (by scratching the jumper on the circuit board) but found only Drive 8. Drive 9 is down there somewhere.
There are all kinds of neat things like this out there. Dang, how cool is that?