[saulrh]

Buy a $20 RC car off Amazon and replace the radio receiver with a raspberry pi for a quick and dirty driverless car platform. Might have to do some surgery to reuse the motor drivers or you might have to add your own, but it's generally not too bad.

[RyanOD]

The most memorable project I ever did as a teenager was building a Tamiya Frog RC car with my older brother.