Blippy, the service that lets you share your credit card purchases with other users, has a pretty funny 404 page, with rainbows, WTFs and of course, magical unicorns. Take a look at the screenshot below and then go to the page and click around for yourself.
UPDATE: Yes, we’re updating a post about a 404 page! It’s actually a TRIPLE RAINBOW if you keep clicking around, and the unicorn runs and jumps!
Big h/t to Joe Stump!