The ridiculous, Cachemonet-esque Bloomberg 404 page
bloomberg.comI recall this being at the top of /r/webdev 3 or 4 years ago. It turns out that a lot of the subsections have their own themed 404s as well.
My personal favorite: https://www.bloomberg.com/politics/404
OMG. That is really hilarious.
Bloomberg are normally described as a reliably joyless organisation, so it's nice that employees are allowed to have SOME fun.
In a similar spirit, the Bloomberg Businessweek magazine used to have zany cover designs (my favorite featured a sweaty Steve Ballmer in a Clippers jersey dribbling a basketball captioned "BASKET BALLMER") but they've since switched to plain, solid colors.
Yeah, my favorite was the animated GIF of a flying Jeff Bezos inside a cardboard box.