For those who don't know, Tivo is a popular recording device for TV shows. Raffi Krikorian, a recent MIT graduate, has a book coming called "Tivo Hacks." It lists 100 different ways that a Tivo owner can alter the features of this device.
The company that makes Tivo is taking a hands off attitude to the book. Krikorian met with them before writing the book. The company warns users that opening these machines invalidate their warranties.
To avoid lawsuits, Krikorian doesn't tell people how to get free subscriptions illegally. He does write how people can increase their storage space, how to change the names of programs and how to create a 30 second skip to avoid commercials. http://www.wired.com/news/technology/0,1282,59028,00.html