Browsing the net, youtube, forums, mails, watch movies, play some games that can end up fast, whatever can be possibly done in the net.
When I get bored of the net, I will find myself a comfortable bed to lie down, play some musics I like, yeah there is some musics that can make me listen repeated non-stop.
Bored of that too? Last time I would say I will decide to have something to eat, but I usually buy the ingredients and cook it myself at home. Now I do not prefer eat anymore, having overweight is not worth it, I need to exercise more for all the food I put into my mouth, so no more eating here now.
No net, no music, no eat, how? Easy.. I just go to sleep or pick something that can make me brainstorm my head and think a lot until I fall asleep.