Back in the 90s when the web was non-commercial and fun, I added a "Don't Click Me" link that loaded a 'browser test' page (after a series of "are you really really sure?" dialogs) that exploited every historical browser bug I could find. Infinite popups, inescapable dialogs, ActiveX quirks, various hangs and crashes, the works.
If it didn't crash your computer, it eventually displayed a single popup that said "Congrats on not using Internet Explorer!". I wish I still had the hate emails.