Switches for things like printers and monitors have been available for ages. Flick a switch and the PC is connected to a different device through the same port, or the same device is connected to the port of a different PC. However, have you ever thought about switching hard drives?[Tech-Mods]Cranking up the computer, everything booted up normally. The switch doesn't operate once the system is running, so there's no danger of things getting accidentally switched during operation. After shutting down the computer and selecting the next IDE channel, everything booted up just like I had literately swapped drives.
A funky device, useful if you want a hard drive all to yourself, but share a PC. However, somebody could just flick the switch and fluff up your hard drive for you... damn them.