I recently discovered Erlang and am now working my way through a couple of tutorials. By now I'm looking forward to actually implement something as a hobby project. I'm not really interested in yet another chat server. I would like to code something more interesting (yes I'm aware that this is a rather fuzzy term) which is also manageable, so I can finish it in my spare time.
Any suggestions?
Edit: The project should preferably highlight Erlang's strenghts (concurrency, distributed).