This is a very basic UNO game I'm developing in GameMaker: Studio.
I started this project mostly to play with my friends so it's not 100% polished.
But if you'd like to play the game, here are the steps to do so:

-Open up the "Uno - Server" project, this will boot up the server.
    
-The server works with the port 50000 so you need to make sure to either use Hamachi  
and have everyone join, or you can port-forward the said port (make sure you disable firewall).
    
-Next you can open up the "Uno" project (preferably make a .exe if you want to play with someone)  
if you're the one hosting the server, you can leave the default IP (127.0.0.1) in "Connection info"  
and then press "Connect to server". However if you're not the host, you need the global IP of  
the one hosting the server.