There's also a VM written in Go by kballard: https://github.com/kballard/dcpu16.go/
And a disassembler in JavaScript by evilpie: https://gist.github.com/2300590
Edit:
CoffeeScript, too (via steverb): https://github.com/Janiczek/cfs-dcpu16
@sp332: I feexed it