Well, I'm thinking about intergroup-wide event to integrate Project Haven, Undead Assault Reborn, The Rising Dead and Pandorium Survivor players. We create groups of random players from random games and play those games just for fun.
Those 4 games are familiar to each other so most of players might/might not played that before. It'll be funny for beginners as well as for veterans.
Example time for event beginning: saturday 19:00.