I was at last year's Formula SAE competition, and listened as one of the design judges commented in detail about the Design Scores, and how low most team's scores were regarding innovation. It's only 30 points out of 1000, but it seems to be the most appealing and challenging to new engineers wanting to prove themselves and change the world.
Well, I thought I'd start a post about it, and start with a proven concept that could use further exploration with modern materials and machining ability: Sleeve Valves
The rules do not state anything about the valve mechanism of the engine, only that it need to be of the piston 4-stroke type. Since single cylinder engines seems to be gaining popularity, and this concept would be easier to explore on a single.
A little history lesson: Sleeve valves were uses to power military aircraft during WWII right as jet engines were being developed for aircraft. The liquid cooled, forced induction sleeve valve engines were achieving mean effective pressures of 350-400 PSI. The sleeve was ported (similar to a 2-stroke) and rotated and recipricated between the cylinder block and the piston.