I've been running the "Prime Number Shitting Bear" at work.
http://members.surfeu.fi/kklaine/primebear.html
It rules! It's just a sketch of a bear, and it shits primes.
I've had it running for 356 hours, and it's gotten to 17645977 (and rising). That's about the 1.1 millionth prime. Now, to install XP SP2, I need to reboot. I guess I'll start over, and let it run on a box I don't do much with.
Also, any browser that doesn't include a JS debugger/console should be shot. At the worst, it should have an outside program to do inspection.