https://github.com/severb/0x10c-asm
https://github.com/tscho/dcpu16-js
https://github.com/M4v3R/dcpu16.go
https://github.com/fbulens/dcpu16-js
https://github.com/AlexNisnevich/dcpu16-assembler
https://github.com/itsbth/DCPU.coffee
https://github.com/isamgray/DCPU-16-CPP
https://github.com/judofyr/rcpu
Not projects on GitHub:
https://gist.github.com/2308725
https://bitbucket.org/1player/godcpu16
I may have missed some projects/gists, but I'm sure they'll find their way here.