I don't have, or know, any kids to buy these for but they look neat.

Lowes has Radical Racers for $20

https://www.amazon.com/Air-Hogs-Grav...15179& sr=8-4

https://www.amazon.com/ANTAPRCIS-Con... 9&sr=8-3&th=1

They run up and down walls and upside down on the ceiling.

One person said his model wasn't sturdy.