If you're in the market for a homegrown Linux PVR, don't have the extra cash to buy something like a Monolith Media Center and have the gumption to put it all together yourself, you'll be very interested in KnoppMyth.
KnoppMyth is a distribution developed by Cecil Watson in an effort to greatly simplify the Linux and MythTV installation process. The most recent version (Release 5 D1) was posted on the My Settop Box site and an extensive listing of changes can be found in this changelog.
The site also houses an active forum should you run into problems building your box.
I can't say I've tried this myself, but the more I read about MythTV the more interested I get in putting one of these together. If and when this occurs, I'll definitely go the KnoppMyth route.
