The BUG, or Basic Ultralight Glider, is a simple bi-plane ultralight glider designed by Michael Sandlin. It is intended to be easy and low-cost to construct, while offering easy, low-speed flight characteristics. It is not foot-launchable, though its large main wheel allows a rolling launch at many of the flying sites frequented by hang glider pilots.
You can read more about the BUG at the official BUG website.