The Times has a pretty good write-up of Microsoft's XP Media Center OS that's coming out. I've seen some demos, and it is pretty impressive, especially since they loosened some of the DRM restrictions. But one of the most interesting parts to me was that the television listings are downloaded across the Internet for free, presumably from Microsoft's servers.
Given that so many Tivo users have hacked network cards and connections into their devices, how hard would it be to write a little piece of software to connect your Tivo to Microsoft's data feed? I'm sure it's an XML format, maybe with some security or compression on it, but a little transformation once the file's structure is figured out, and you've got a keen little service that would be pretty damned hard for Microsoft to figure out a way to stop. I just can't imagine they check the registration of the client machine each time the update runs.
Get cracking, kids!