Lego Technic is perfect for creating quick prototypes of pretty much anything, combine this with RC stuff and you can create really fun stuff. One simple example is the robot i describe in this post:
Sunday afternoon robot
My old Lego is usually stuffed away in a box in the basement, but when we have kids visiting we usually bring it up to the apartment. I suspect I’m the one enjoying it most and this time I built a RC lego car
After a few testruns I added a propeller protection bar to minimize the risk of running into something with the propeller.
Runs great, I’ll probably update this post with a video when I’ve recorded one.