1. On Windows: Minimize the ad window (don't close it!). That'll tame it for a little while. You can also just push the front window over top of it. It'll stay behind that one and keep reloading for a while.
2. On Mac- double-click on the title bar- this should shrink it. If you're on MacOS8 and above, there should be a little box in the corner (2nd one from the right) that will do that with one click for ya. After that, bring the chat room window to the front and type away. The ads will keep reloading in the background.
3. And of course, the easiest way- Disable Javascript and Java in your web browser. In Netscape, go under preferences and click on Advanced. Uncheck those boxes. No ads! :)