I would have them build anything and everything with the caveat that no matter how good they were (or weren't) the quality of their code would suck looking back in 5 years and to start with bad code, and incrementally add concepts like switches, functions, etc., much like very young coders did at age 10-15 when building anything, in any way was cool beyond belief. Solving problems better and better is the fuel of continuing to learn to develop better for me, but we all have to start somewhere.
Therefore start solving interesting problems. And keep solving them until you get better at it.