Thinking back on my own schooling, I remember that with the software I enjoyed learning, I'd always venture off into random ideas I had, but even though that was valuable for my learning, I never got credit for it. Sometimes I still did it, other times I stopped because my time was limited, I needed to focus on the content for the class.
Anyway, the point is, at the end of each module my students complete, I give them an Open _________ Project (fill the blank with the software you're teaching). It gives students a chance to create whatever they want. When they turn it in, they basically get completion credit—I don't want to put pressure on something called "open" because then it would be anything but. About a third of my students waste it and just create something stupid for credit. That's fine. Another third simply do one of the assignments again because they thought it was fun. Even better. But that last third (I'm making up proportions here, it might be more like 20-60-20) do something amazing, like this:
I can't imagine the thought process that went through this girl's head. "You know, Tom Cruise's hair reminds me of a lion's mane. I ought to bring that idea to life. Since it's so dreamy, maybe I'll put it against a space background. Yeah, now it totally captures my fantasies."