[Accujack]

Check out the Xilinx "Zynq" series of FPGAs. They have a lot of uses.

[rcxdude]

In that case the CPU is basically the co-processor for the FPGA. I've yet to see a use that wasn't primarily using the FPGA because it needed to be an FPGA, they're not great if you just want to run something fast (outside of a few small uses).