The team at Tested got a chance play around with Team Fortress 2 using the upcoming Oculus Rift headset, and they recorded half an hour of gameplay for us to virtually enjoy. Not "virtually" as in we'll "almost" enjoy it, but "virtually" as in "virtual reality"-based enjoyment. Just watch the video.
Kickstarter backers should receive their Oculus Rift dev kits by mid-April, with pre-orders hitting a little later in the month. For those expecting a kit, check out Valve's list of handy tricks for setting up VR in TF2.