Erlang Wordlist Generator (ewg) is a brute, opensource and parallel wordlist generator written in Erlang/OTP. Internally there are the following parallel processes (gem_servers):
Erlang is a robust functional programming language, ideal for building concurrent distributed systems. Erlang allows for a flexible design that is easily scalable and readily extensible.
See http://github.com/matteoredaelli/ewg/ for details