The Experimental Rocket Propulsion Society (ERPS) is primarily concerned with building liquid fueled rockets. However, they have to do a lot of work with flight control electronics and decided it would be much easier and cheaper if they could test their work with a resuable vehicle that could be flown inside the city limits. So, they came up with the ERPS GizmoCopter, a four rotor, VTVL vehicle controlled by a PC/104 processor running a real-time variant of Linux. The flight control software, OpenVTVL, is being developed by ERPS in cooperation with Armadillo Aerospace in Dallas, TX, another group trying to develop a liquid fueled VTVL vehicle (led by none other than John Carmack of Id Software fame). OpenVTVL is being released as Free Software under the GNU GPL.