Learn about and install linux
(recommended first done on an old computer).
Seriously? The internet is pretty boring to me, too. The only sites that I check regularly are this one, xkcd, and occasionally the enfpforum. Oh, and email, if it's during the school year.
I actually violently hate personal computers, internally. It's not like I can blame them for my lack off willpower, but going through old emulators/roms is like a black hole for absorbing my time. I wouldn't miss these things if I didn't have them (and I don't miss them, when I don't have them), but I still somehow end up wasting tremendous amounts of time playing them, when they're available. And at the end I don't feel like I've gained anything.... I just look back and think "where did all my time go, and why the hell did I feel the need to play through destiny of an emperor again?" Playing around on computers just makes me feel empty inside.
However, getting to know how linux works is actually a lot of fun, mentally stimulating, etc... if you're into that kind of stuff. Probably not a bad skill to have if you're looking to get a job somewhere either.