Bartok is a card game in which players may modify rules when they win.
You play a game of Bartok (initially similar to Uno) and when your hand is empty, you may submit code that modifies the rules.
This can be played at http://3dox.uk and you can test rules by starting games where the name of the game begins with the string "TST".
For an introduction to writing rules, see Tutorial. TLib is a framework for writing rules. TSample gives examples of rules written with this framework.
You can also find documentation here.
Assuming you have Stack, the following commands should get it running:
git clone https://github.com/penteract/Bartok.git
cd Bartok
./serve
(serve just does stack build && stack exec server)