Have you heard about the game of Piss Poker? Folks have been playing it regularly in San Francisco for years now, and there are probably games being played elsewhere as well. You can read all about it at http://poker.pitboss.ws. Another game will be scheduled soon, and when it is, you will find the details about it here.
Below are listed some venues that publicly allow and encourage piss play in designated locations and/or at specific times.
Below are listed some online resources of interest.
More to come. This is a California list only, for now.