I've given up TV before. Began in University, relied solely on radio (music and talk). Managed to go without any form of entertainment TV (not even videos or, once mainstream, DVDs) for months on end.
These periods would be interrupted of course by the times I went to stay with my parents (which was very seldom while at Uni - usually during the major vacation periods). Going back to TV during those times, I would be caught out a lot by the various trendy TV shows at the time, and even be confused by the new channel idents.
Yet, going back to University for the next semester, I would not miss TV at all. When I moved into a flat for my second year, my flatmate had a TV but I chose not to watch it. There were moments of course when the TV would be on and something fleeting (like Futurama or The Simpsons) would be on, and even then I caught the first season of Enterprise when it was on both Sky One (as it was called back then) and Channel 4. Once I got a decent internet connection, the Internet took up much of my entertainment time, more so than games.
I survived without TV, but of course I did miss out on various shows the first time like 24, The Office, The League of Gentlemen, Spaced, etc. - only revisiting them on DVD once I started working. Then, in my second year of working, my mother reminded me that I ought to get myself a TV, and I started watching again. Thanks to the likes of the revamped Doctor Who and LOST, now I feel there is some TV worth watching. Although I can definitely give up any time I wanted - I mean, I watch neither Strictly Come Dancing
nor The X Factor.
I haven't given up on my radio.