As I write this I'm in a coffee shop in East Lansing working on a game with some friends, Jon Kuperman and Kelly King, as well as Enrique Acevedo, a financial guy we teamed up with. We're here for Lansing Startup Weekend, and our project is a geolocation based monster fighting game that can be played mobile or in the browser (mobile is more accurate).
You can currently play a demo of the game at zyu.me:4000, however it isn't guaranteed to stay there forever, and you won't see any monsters unless you are in East Lansing.
In the game, your character is based on your current location, so to interact in the game world you need to move around in the real world. Monsters spawn in random locations, and your job is to slay and/or capture them. Once you incapacitate a monster, you have the opportunity to walk up to it and claim it as your own. Your character never fights though, only your monsters.
You can tell your monsters which wild monsters to fight, or even which tame monsters belonging to other people to fight.
Players will always be playing the game, even when they log out. Tame monsters will always be in close proximity to their masters. At night, as the player is logged out at their home, their character will be walking around the area of the house. Players will probably wake up and find a bunch of incapacitated wild monsters at their doorstep, much like a cat would do with mice in real life.
There's a few ways to make money on this project. One way is through micro-transactions. For example, a player could buy potions to heal their monsters. Players could buy a talent for a monster that allows them to claim incapacitated monsters so that the player doesn't have to walk so much.
The cool way to make money though would be to have a local business represent a monster hospital. That business would pay us a monthly fee to have their business be a special zone, where players would need to spend some amount of time. After hanging out at Starbucks for 10 minutes, your monsters could be at full health.
This project was fun to work on. I've worked with multiplayer map code before with Cobalt Calibur, and I've worked with GPS based multiplayer interaction before with Whisper, and this game was a cool way to combine the two. The game is currently incomplete, but depending on our excitement we may complete it in a weekend or two.