This is a nice skinny BoeBot wheel for making a mars rover type looking BoeBot or other vehicle ... the hub ties to a servo motor.
The extra rectangular bumps help to keep your rubberband tire ON and Centered.
This is another of many entries to the makezine.com/go/makerbot contest ...
blog.makezine.com/archive/2010/04/makerbot_giveaway.html
The first pictures sent in from BG of some of my designs ... the wheel and servo brackets ... bottom left ... I guess I'm not too far off ...