Ok, so it wasn't a huge or clever hack, but it was new to me so here's the story...
As of this writing, I've had a Tivo box for about a year or so. I love it, its great, and I don' think that I can live without Tivo from here going forward. Well one day we fired up the Tivo and we found that we suffered the green screen of death. At first we didn't know what the green screen of death was, but after reading some of the error messages on the Tivo screen and googling we learned. In our case what we learned was that the hard drive had failed. After checking around we learned it was going to cost us $140 plus shipping (probably at least another $40) to get it fixed. After spending so much on Tivo and having it only a year, I said "No way".
So I fixed it myself for about $80 bucks. I found a company that for a nominal fee will provide you with a boot-able CD-ROM that contains software to format a Tivo hard-drive. So you basically buy a new drive, stick it in an existing PC that will boot from CD-ROM, boot with the purchased CD-ROM and follow the instructions. After prepping the drive in your PC, you place the hard-drive in your Tivo box and hurray, your Tivo works again.