Mobile multiplayer location based zombies
I Know What You Did Last Summer: Game world is persistent between sessions and changes from one session affect game play on the following ones.
More the Merrier: The game is a competitive or cooperative multiplayer "party game" (i.e., based on minigames, humor, 4+ players, audience engagement, etc.), meant for one screen or more.
X Marks the Spot: The game involves something location-based, such as a geocache, or requires the player to go to one or more specific geographic locations.