The Spherical Drive System Bike is a project being undertaken by students at the Charles W. Davidson College of Engineering at San Jose State University. The students are currently building a prototype of this outside the box locomotive design.
The Spherical Drive System Bike will run on tires shaped like -- you guessed it -- spheres. The wheels are made from carbon fiber and fiberglass, and the spherical wheels should make it possible to move in any direction hypothetically. The creators argue that this will make the bike safer, and more fun to drive. The bike will also be self-balancing, so that you don't tip over.
I can't help but think of the motorcycle from Batman when looking at this design. If the two are anything alike, this will be one killer motorbike.