As a testament to its tinyness, you probably have to squint just to see where the thing is that's holding up the bicycle in the above picture. Granted, it's a little camouflaged by the white wall it's attached to; but still, believe it or not, the Clug ($25 with shipping) at the base of the front tire is all that's keeping that bike in place.
This small, space-saving wonder is available in sizes to fit road, hybrid and mountain bike tires. It can be installed just about anywhere (as you'll see with the tree in the below video). And depending on which model you go with, it comes in as many as two outer and four inner colors.
It's not only handy and innovative, but—let the record show—one of the only times you'll hear us strongly voting in favor of getting your hands on the smallest rack possible.