When you've got nothing to do at work, what do you do?

I've got no students coming to whinge or ask stupid questions *knock wood*

I've got no paperwork to file (I'm dependent on my co-workers for that, anyway) or mail out.

The phones aren't ringing *knock wood*.

I've finished the project my boss set for me.

I've answered all my email.

My desk isn't very messy at the moment, so it doesn't need to be cleaned.

I've read just about every story on the BBC news website.

I've read the Residence handbook yet AGAIN in an effort to educate myself. I may go read the manual yet AGAIN.

I have to look/sound like I'm doing something. Don't get me wrong. In a month we'll be swamped with applications and I'll be whinging about being overworked - I know that's the case. But for the moment...

What would you do? Surf the 'net? Organize your desk yet again? Help!