A French company has made it possible to take ordinary kicks and turn them into roller skates. Flaneurz' On Wheelz can put a set of wheels on sneakers (or other shoes like Doc Martens) simply by clicking them on. (Well, that's after you send your shoes to the company to be modified so the wheels can be simply clicked on. Or you can buy one of their pre-modified pairs.)
Something this cool doesn't come cheap. A set of On Wheelz with modified shoes costs between 380-475 euros (that's about $467-$588).