[solistice]

I second the suggestion to get them to get started with simple hardware stuff. There's nothing nicer than getting your first little robot running.

I'd reccomend showing benefit first and then getting them to tinker with implementation, so you maybe want to preassemble the first one and demo it to them and let them play with it and program it once they're allready excited about the prospect of doing that.

Afterwards, I think the most sensible option would be to modify some lego 9V motors [shop.lego.com/en-DE/LEGO-Power-Functions-M-Motor-8883] to interface to an arduino motor driver shield. That way, they can tinker around with the structure of the robot as well, and legos lend themselves to creative tinkering.

Much later, you might want to get them into programming robotic arms or small quadrotors using C, but even if you get them intrested in it, it might take a while to get them to a skill level where they can do so.