Had to design this for another larger project, but thought it is cool on its own as well. Has an iCE40Lite with 3520 LUTs, internal power supply for the FPGA, 4Mbit configuration memory, and even 1Mbit serial SRAM.
The whole thing fits into a standard PLCC28 socket - small enough to be worked with conveniently, yet not ridiculously small as the raw FPGA chip itself, which is a micro-scale BGA and not really user-friendly. Haven't got much else to tell yet.

Ah, yes. Had to design a programmer for it too, that takes a bit file from the PC via USB and loads it into the configuration flash, or into the FPGA's NVM. How about that? ;-)