How do you shop for someone you don't know all that well?

I need to buy a christmas gift for a person I don’t know all that well. I’m very close with his wife, and I know just what to get her, but this is a surprise, so I can’t ask her. He has done a lot for me, so it would be kind of rude for me to not get him something.

I could get him a gift card, but he doesn’t shop much. He’s not big into technology so he has no use for amazon gift cards, digital music, ebooks, etc.

Tell me your secrets. I’m stuck.