Ask HN: How to convince someone to do A when they really want to do B?

I am trying to recruit an engineer who really wants to do game development, 3d graphics, etc. We are mainly a Python/Django shop as far as back-end is concerned. There is some Java stuff to be done down the line but it won't be open for a few months at least. My selling point is that the stuff he will learn will be pretty much transferable. He will get to be working on something really cool that touches a couple of thousands people in a very significant way. We are making impact at a relatively larger scale on each and every user of our product. But this person is so much tied to a very specific domain. What would you do if you were recruiting someone like this person. I come from a web dev background so I have always been open to learning new tech with product goals first in mind.