I wrote my first program in QBasic (!) Somehow I ended up with a floppy disk which contained the game nibbles. I was playing around with the computer and realized I could look at the source code. Then I started messing around; I wrote a guitar tuner, and a quiz program.

Seems like the biggest hurdle will be getting them interested and thinking for themselves (for example, if you ask them to write whatever kind of program they want, how the heck are they going to know what's possible?)