Party Golf Online

Download the zip. Run the EXE. Click on some of the dodgy on-screen buttons. Win.

In running from the command-line, there are options:

-mlapi host: be the server (and also a player)

-mlapi client: connect to the server as a player

-address aaa.bbb.ccc.ddd (i.e. an IPv4 address). As the host/server you should put your extenal IP address here, as a client, you should put the server's address here.