Tickle Shows the 404

I got this handy 404 from Tickle in a pop-up today:



Well, of all the 404s I've chronicled, it's the best. It makes it look as though I requested the pop-up ad, and if I am patient and refresh it, I can see Einstein's mug or a quiz to determine my real IQ.

By the way, how do you upgrade a pop-under ad, and do I really want to know?