Why not have them program some games? Start with something simple like a dice game or a reflex tester. If they dispense with that easily maybe show them a little Tk or SDL so they can add graphics. Or perhaps do it with CGI and HTML, which might be a little easier to learn and ultimately more useful.

I spent a very enjoyable year in junior-high programming a hilarious choose-your-own-adventure in BASIC on an Apple/II. Armed only with PRINT, IF, GOTO and READ I had a blast. Just imagine what I could have done with a teacher!

-sam