I'd love for this to get more mainstream attention! J, Futhark, Accelerate all have very neat stuff under the hood.
I second J and Futhark. I love J, and I wish there was a way to use the GPU with J. I have looked briefly at APL -> TAIL -> Futhark, but I don't know enough to do something useful with that particular toolchain or wow myself enough to keep going. More studying...
How about co-dfns? CUDA accelerated APL!