What to do with an old G5 Tower?

lunatic1969 writes: I've got an old G5 PowerPC tower that's sitting in a spare room not seeing much in the way of use. I'd like to stick a linux distribution on it and maybe breath some life back into it. I've got a few vague ideas. It might be a handy file server, streaming video for a security system, or simply just to have a spare box around. My question is therefore in two parts: First, are there any particularly creative projects or ideas anyone has for an old G5, and second and most important, which distribution currently offers the best support for this box?