I had a friend in college who built his own DVR with an old desktop computer. The quality was somewhat poor and I thought he was a little crazy at the time -- I said what's wrong with your VCR. I'm sure folks that built the original Mp3Cars were looked at as pretty crazy as well - Apple didn't seem to think so.
But as technology gets better and better neither idea seems too crazy.
So for those of you not wanting to fork over $200 on a TiVo or pay for the monthly subscription, Lifehacker has instructions on building your own DVR with a desktop (or laptop for that matter) PC.
If you can install a PCI card and some software, you too can build your own DVR. Give it a go and let us know how it works out.