I think it depends on the age. If he/she is 9-10-11 I think a fun combination could be a Lego Mindstorm robot that is controlled in C. You don't have to learn

I think it depends on the age. If he/she is 9-10-11 I think a fun combination could be a Lego Mindstorm robot that is controlled in C. You don't have to learn them pointers from the start, just let him mess around with the basic stuff such as data types and functions. I think you should focus on results; getting a robot to do stuff could spike his/her interest because its 'cool'! A command line window might look dull.