Multiplayer Spacewar over websockets built on Erlang with Cowboy.
Before you try running it for the first time:
$ rebar get-deps
$ rebar compile
And launch Erlang with the correct ebin folders available:
$ erl -pa ebin/ deps/cowboy/ebin/ deps/ranch/ebin/ deps/mimetypes/ebin/ deps/mochijson2/ebin/
And in the Erlang shell:
1> spacewar1:start().
Go to the following link (assuming you've run it locally):