I've been using AdBlock Plus, a completely free add on for Firefox, for a few weeks now and it works wonderfully. It blocks those find your high school classmates, shoot the duck to win a free iPod Nano, and a whole bunch of other ads. Plus, if there is an ad it does not automatically block, you can tell it to block it.

:arrow: https://addons.mozilla.org/en-US/firefox/addon/1865
You'll need the free Mozilla ad-on master Greasemonkey if you do not already have it: https://addons.mozilla.org/en-US/firefox/addon/748

After you've installed it, check out the forum pages on A.net. The ads are gone.

And if you don't use Firefox, this is all the more reason to switch.