If you have steam installed you would have noticed a strange update over the last few days to some of the more famous games, such as the Half life episodes, portal and even Team Fortress 2.
The update is for the Novint Falcon, a new FPS game controller device. Basically, if a joystick is the right controller for a flight sim, the falcon is (supposed to be) the right controller for a shooter game.
It's been out for a little while, but these days it's pretty much a gun handle connected to a device that, probably totally by accident, looks like the portal gun itself. There are several levers that keep the gun handle in place, but when you move it, these move and tell the computer which way you want to look. You can then aim and fire as if you were holding a real gun.
The idea is sound, but it looks a little alien to me right now. I think I need to have a go with one to see what it's like! But I'm not ordering one from America with those ridiculous postage costs. Plus the pistol grip part is not available for sale in the UK anyway!
Anyway, here's a demonstration video of it in action. The next best thing? Or the next soon-to-be-over fad? Who knows...