I would build a robot as a Drone that shoots Nerf harmless arrows! You could then have fun battles between friends.
By myriaddev
Other robots from Synthiam community

Cosplaying's Project Mini Rover
i tried to keep my second project as small as possible, and i think it turned out pretty good (though i need to get rid...

Daman's Yet Another Wall-E
So I built my Wall-E months ago after receving it the day after I finished Metal Box-Bot, but I havent got around to...

Ezang's RGB Arduino, Python Code With ARC
Here is an example of using the ARC serial monitor I am using an Arduino, Python code, with ARC - watch the R G B light...