You can't anymore. When there used to be a single ad in a top frame, there was a way to work around it. You can probably resize your browser window, however, by dragging the right edge over so the ads disappear (but would still be there if you scroll right) Barring that I suppose you could tape a long piece of paper over that side of the monitor when you're on the site
I keep the browser window drug over to the left so the ads are covered. I wouldn't mind the ads if they weren't flashing and jumping all over the place. They make me motion sick. I think they're defeating their purpose because they're so annoying you can't stand to look at them.