The man with 1,000 Klein Bottles UNDER his house - Numberphile
Klein bottles are kind of fun, like a Mobius strip. Unlike a Mobius strip they aren't really good for anything, at least not that I know of. But the video isn't really about Kein Bottles, it's more about compact warehousing and homemade warehouse robots. Reminds me of an automated package delivery system. You don't really need a big fat truck to deliver a five pound package, or even a 50 pound package. Some cities, notably Paris, has pneumatic tubes for sending messages. London has a miniature railroad for transporting the mail.
Video via Iaman.