Well, last year at Oshkosh there was the EZ Rocket. This year brings this—a Pulse Detonation Engine (PDE) strapped to a Long EZ. This plane will never fly but one similar to it may fly as early as this fall. Scaled Composites has been contracted to build and fly a manned testbed for the PDE. The engine was developed by the Air Force Research Laboratory (AFRL) at Wright-Patterson AFB in Dayton, Ohio.
Innovative Scientific Solutions is a consulting firm involved in the project. Their web site offers a simplified explanation of how the PDE works plus a number of research papers for the more ambitious.