A collaboration between Disney Research Zurich and Autonomous Systems Lab at the Swiss Federal Institute of Technology (ETH) has yielded the VertiGo, a sort of RC car/drone hybrid. 

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The lightweight four-wheel vehicle features a pair of tiltable propellers, and since those propellors can tilt independently and provide thrust in two different angles at once, the VertiGo can pull off a rather neat trick:

The robot is able to move on a wall quickly and with agility. The use of propellers to provide thrust onto the wall ensures that the robot is able to traverse over indentations such as masonry. The choice of two propellers rather than one enables a floor-to-wall transition - thrust is applied both towards the wall using the rear propeller, and in an upward direction using the front propeller, resulting in a flip onto the wall.

And don't let the Disney name fool you; the VertiGo is no toy, but was developed in order to "[extend] the ability of robots to travel through urban and indoor environments." I'd love to see if they could get this thing up to the ceiling, where it could clear cobwebs, change lightbulbs and put fresh batteries into the smoke alarm.