GSOC 2011 project, I would suggest Mono.SIMD. If you don't already know what SIMD is, then this project probably isn't for you, but you might find it interesting nonetheless. Although the Microsoft .NET version of C# does not explicitly support SIMD, once Mono has it for x86, ARM, and others, Microsoft likely will want it as well. The ARM port is just as important (if not more) important than the x86 port, so please don't ignore it. Buy a BeagleBoard or a PandaBoard to tackle NEON SIMD, (or even buy a Plug Computer or Verdex Pro for iwMMXt) . Although some people may think that iwMMXt is old news, it still lives on with Marvell's Sheeva and ARMADA product lines. You can still do blazingly fast multimedia with iwMMXt (h264, for example) but its limited to integer operations rather than floating-point (which is more efficient for multimedia in any case).