Little battery powered electric helicopters are lots of fun, but they tend to crash into stuff without an expert hand on the controller. One solution is to make a helicopter that can guide itself using GPS, but this doesn't work too well indoors where there are no useful GPS signals.
Boosting their ultra tech-nerd credentials to the highest level possible, the Robust Robotics Group at MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL) built this quad rotor heli that uses a laser sensor to draw a map of obstacles and room boundaries, allowing it to fly safely without human input.
Why do I get the impression that the US military would love to talk with these guys?
MIT TechTV, via MAKE Online