Homebrew Cray-1A
chrisfenton.com
chrisfenton.com
[1] : http://wayback.archive.org/web/20130807191943/http://www.chr...
[2] : http://modularcircuits.tantosonline.com/blog/articles/the-cr...
Hey I have one of those Digilent spartan 1600 boards at home! Those are nice boards. Needless to say the cray is not going to fit in a little CPLD, and a 1600 is moderately big for home use. The Xilinx software to compile and download bitstreams is not open source but is free and trivially installable under Debian linux. I have a very long G+ post explaining how to go from a bare Debian linux install to compiling and running CPLD code, but it boils down to, other than taking a long time and being a PITA there's nothing terribly difficult about it. Its fun and easy to mess with FPGAs/CPLDs at home. Xilinx uses basically the same software (plus or minus various utilities) to program their whole line from five year old CPLDs to the latest FPGAs.
You can also download 80s microcomputers, PDP10s and PDP11s, PDP8s, all manner of classic fun onto a FPGA of that size.