I'm starting to REALLY like this guy that doesn't know me very well.?

He doesn't go to my high school, but I've known him for a while from cross country. At the new england championships in november we talked a bit and I began to like him, but then I didn't see him for a while and it went away. Then I saw him again today and I'm flat out infatuated! He barely knows me (and frankly I don't know him all too well), but he's hilarious and so cute and for some reason I'm starting to really like him! I don't have his screen name, email or cell number. What can I do to either 1) stop obsessing or 2) get to know him better without seeming weird and stalkerish.