Wouldn't it be neat if you could turn an old laptop or desktop into a media centre that served and streamed movies, music, and files, and even backed up your other systems? With an Amahi installation, it's not too hard.
Amahi is really a repository you add into an installation of the Fedora Linux system, but when you do, it gives that system a whole new look and purpose. From a web interface you can access from anywhere on your network, Amahi can organise and offer up access to movies, music (with streaming to iTunes and other players), photos, calendars, Outlook systems, and any old files you're in need of. Amahi can also set up a VPN for your household network, giving you remote access to your files without too much more geeky configuration than the standard setup.
Amahi can run on pretty much any system that Fedora 10 can install on—that's about a 1.0 GHz processor and 256MB of RAM minimum. The developers are working on versions for Fedora 11 and Ubuntu, but for now, Fedora is just the base of home server that doesn't require an expensive licence purchase or mastery of Linux to install. Free to download, works on any x86-based system.