Just like you, if I'm up at 4, I'll fire up the computer in my room and browse my bookmarks. In no particular order thay are: this board, Fark, /., the Boards attached to my tagline, the USENET, snopes, straight dope, skepdic, wikipedia. It kills an hour and I'm sleepy again.
Going into the living room and fireing up the T.V. seems like surendering too much -- that means I don't expect to sleep again that night. Besides, if I watch what I have stored on Tivo at 5 AM -- what will I watch later when I'm bored in the evening?