Tim modified some kid-sized jeeps with laser tag weaponry + game controllers to create a live action game in the spirit of Halo’s warthog vehicles. In the above interview he explains the sizable list of gear used to make it all happen. I’m guessing a simpler take on the idea could be built using RC vehicles with infrared sensors and emitters. A full rundown of the build can be found over at Microsoft’s Coding4Fun blog.
Power Wheels car modded into wireless warthog