OK, it will only run five miles around central California, and it won't come anywhere close to the 800 mph Musk promised, but it's a start.

The Hyperloop, detailed by the SpaceX and Tesla Motors CEO in a 57-page alpha white paper in August 2013, is a transportation network of above-ground tubes that would span hundreds of miles. Thanks to extremely low air pressure inside those tubes, capsules filled with people zip through them at near supersonic speeds. 

The idea is to build a five-mile track in Quay Valley, a planned community (itself a grandiose idea) that will be built from scratch on 7,500 acres of land around Interstate 5, midway between San Francisco and Los Angeles. Construction of the hyperloop will be paid for with $100 million Hyperloop Transportation Technologies expects to raise through a direct public offering in the third quarter of this year.