Tivo set top box with a hard drive in it. You can set it to record several things at the same time and also watch, rewind, and pause live TV. It does this by recording to the hard drive. You can buy Tivo at any big store like Circuit City, Best Buy, etc. The boxes aren't cheap. The cheapest one I have seen was $200. There is a monthly fee for the programing information it downloads ($12.95 I think). You can't get Tivo on your PC but you can make your PC function like a Tivo if you have a tuner card. With software like
Myth TV your PC will become a Tivo and much more. If you want to record more than one show at once on your PC, however, you would need more than one tuner card. The advantage to using a PC is that there is no monthly fee. However, the cost to build a deticated "Tivo" PC is about the same as a lifetime subscription to the Tivo service ($499 I belive).