Things to do in work when your brain is dead

So, I've been back in work for a day and so far I have successfully managed not to actually do anything that could be construed as work.
I have had some serious personal internet time, caught up on lots of emails, played spider solitaire for an hour or so, updated my blog, read other people's blogs...
You might think that I would be very proud of myself for sticking it to the man. But I'm actually having a small crisis of conscience and I am so bored right now that it's not even funny.
I'm about to go for an extended coffee break and then make a serious effort to find out my login ids for various applications and even try to do something constructive for the rest of the day.
Maybe.