Go online once in a while. Going online is one way to have fun. Try playing games and socializing. Find new friends or beat old scores.
Explore new songs and movies. Stay off the songs you used to know: while you are youtube-ing your favorite song, try to look at the side bar to find new singles and listen to them instead. Try to choose a new favorite. Equally, search for new movies; search for the latest movies or just any title that comes to your mind and enjoy something different, perhaps in a genre you don't normally watch.