How can I ask him out?

He's late 20s-30 years old max while I'm 22. I will only see him a couple more times until I'm done w/ that course. I need a casual, not-so-obvious way to ask him out. I am too shy to be blunt and say something like "Hey, I'm hungry. Take me out to eat" so I'd have to tweak that and be more subtle. What should I say? Plus I'm worried that I may be out of his league.