POW!

From AnalogX:

With all the cool things about the web (like my website), there's an even greater amount of really lame things, like those popup advertisements from sites like GeoCities and Tripod. After a late night of closing those damn windows, I couldn't take it any more, and AnalogX POW! was born! A simple utility, just run POW! while browsing on the net, and when one of those nasty popups appears, POW! will automatically close it for you... It's that easy! And that's not all... You can configure POW! to close any new popups that you run across, so if it doesn't close them already, you can easily add/remove them at any time. This is an absolute must for anyone who spends any reasonable (or unreasonable) amount of time surfing the web.