How to approach someone?

Alright, so there's this guy and I wouldn't really say I have a crush on him, its more like I'm curious. But not in a obsessive way or anything. I don't have him in any classes and we only talked barely once before, but when we did he made me laugh really hard. That was a like a month ago, and I think it might be weird if I just go up and talk to him since I don't actually know him. What should I do?