Well, you kind of screwed this one up. Only after you tossed him into the ocean did you realize he was a catch.
The first thing you need to do is really determine whether or not you like him. Did you just discover that he's great, or are you only interested now that you feel like he got away? Really think through this, because the worst thing you can do is say that you actually like him only to decide a week later that you don't. That's the kind of thing that ruins your karma for a long time.
If you do actually like him, then you need to tell him. Don't just flirt, but actually tell him. Ask him out, and make it very clear that you're asking him out because you like him. You don't have a lot of time, because I'm sure someone else will grab this guy soon. So go! Go now!
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Do Guys Put Girls In The Friend Zone
I second what MM says. I was in a very very similar situation to yours and ended up doing what MM says is the worst thing you can do. After friend-zoning him, I ended up confessing that I was wrong to say there was nothing between us and that I actually did want to give things a shot. I realized too late in the game that what I missed was the attention and I didn't really have feelings for him. I just wanted a boyfriend and here was this great guy giving me attention, but as soon as he started flirting with other girls and not me I started to think that I maybe really was attracted to him. Needless to say it did not end well, we're friends again now but it took a LONG time for him to get over being angry at me and he had all the right to be. SERIOUSLY think it through. For the sake of your friendship.
the same thing happened to me except he friend zoned me! which is even worse. uggh :(