The Pocket BikeOkay, there's not much to say about this one except that it's equal-dose silly and awesome. That guy's actually really good to keep his balance and make it work. I'm sure it's harder to do than it looks here...
I would guess this video was shot somewhere in Russia, as the YouTube title is russian for "Minivelo! Small, but very fast!".
If you have more info about that tiny bike, let us know in the comments. I'm really curious to know if it was a DIY project or if this thing is actually commercially available. Thanks.
See also: The $9 Cardboard DIY Bike (Video)