As Rampy put it:
BYOPVR is dedicated to Building your own Personal Video Recorder (PVR), Personal Video Recorder (PVR), or Home Theater PC (HTPC) from scratch using PC parts and software.
It’s much more fun, geeky, and flexible than buying a commercial PVR like Tivo, or ReplayTV. You can’t play MAME on your Tivo (well not yet — those TiVo haxors are pretty enterprising).
Advances (and price drops) in video card technology, small form factor PC’s, and Open Source Software PVR solutions have made rolling your own much easier than ever before.
If that sounds like you bag, come on down and discuss the finer points of building your own tivo-esque PC. =)