DC! I remember lots of great days spent playing that thing. I still have mine here. I know about the best thing you can do with it, hook it up and play some games. That does sound quite a bit sarcastic, however there are other things you can do with it. You can make a bootable linux cd. Get the DC mouse and keyboard and you have yourself a small little linux computer. Hook it up to a network and you can use it as a webpage server or some other kinds of servers, it's small and quiet and resonably fast enough for some basic server stuff. If your not into that however, like I said before... playing games is about the best use for it.
DC was such an underrated console. Far better than the PS1 as far as hardware goes, it's sad it didn't catch on more. Really is a great system.