Walk up to him and ask! Maybe he notices you but is too intimidated to approach you. Maybe he doesn't notice you, and maybe he's noticed you but isn't interested. You'll never find out unless you take a chance! The worst he can do is tell you you're not his type, in which case it's better to know that now instead of wasting time mooning over him.

Strike up a casual conversation and be as confident as you can (even if you have to fake it)! Confidence is a major factor in how appealing you are to men. There is something about a confident woman who is comfortable with herself that makes them immediately take notice and become interested (whether you look good or not - trust, I've had guys hit on me when I felt like crap and was wearing the most comfy, baggy sweats I could find). So, pick a day, get all dolled up (in casual everyday, but sexy as hell attire - whatever you got as long as it's one of those outfits that make you feel like you're untouchable) and "accidentally" bump into him and spill your purse or drop your books or whatever you may have in your hands. With any luck, he'll stop to help you pick up what you've dropped and then all you have to do is not let the encounter be rushed. Apologize and when you stand back up, smile and introduce yourself without waiting for him. Shake his hand and hopefully there's a connection and you can play off of that connection. Whatever you do, make that kind of an introduction brief but memorable. (It's real sappy love story kinda stuff, but it could work.)

Another way to go about it, is to just walk right up to him when he is by himself or finishing up a conversation and, without sounding like an obsessed crazy lady, say hi, introduce yourself and simply ask if he'd like to have a cup of coffee or a drink with you sometime. If yes, exchange information and call him the next day to set it up. If no, don't be overly emotional, just say OK, no worries, just thought I'd give it a shot. Don't leave room for awkward explanations, say thanks and casually walk away. Oh and immediately thereafter, buy a pint of Ben and Jerry's, a sappy love story and move on. At least you'll know and will have had the confidence and the strength to take a chance and find out for yourself!