You could make it a home server, making you protected behind a ICS Firewall, or you could make a Digital Video Recorder (if it is fast enuf and supports a TV card, and a HDD), You could make it a small simple computer for a child to have fun on, Make it a Linux / Windows box, whichever you dont have, Make it a base station for Digital Pictures with the RCA jack you can plug it into the TV and have a SlideShow machine
Just a few thoughts, I know I could find a lot of things to use them for
