Compiling my own SPARC CPU inside a cheap FPGA:
https://news.ycombinator.com/item?id=21303446
(https://www.thanassis.space/myowncpu.html)
Thanassis Tsiodras takes an old, cheap Pano Logic G2 (thin client hardware box), and repurposes its FPGA to create a custom CPU...
Well, I'm curious... what other cheap FPGA-containing products might there be out there?