A redditor built a XBox 360 controller into an airsoft rifle. He used an Arduino Pro Mini and whats looks to be a Inertial Measurement Unit (IMU) with 9 degrees of freedom (3 axis gyro + 3 axis accelerometer + 3 axis magnetometer/compass) to replace the analog sticks and allow it to be aimed naturally.
I have stripped the main board of a 360 controller, rewired all of the buttons and joysticks, spliced a micro controller and gyroscopes in to replace the look stick, mounted everything in an Airsoft Rifle making the controls as natural as possible, and will be mounting a screen just in front of the users face so that as you aim your field of view moves just as it would if you were aiming a real rifle!
This would make an amazing, and cheap, engagement training setup. Someone needs to Kickstarter this asap.
[ Many thanks to Reginald for emailing us the link. ]