Rule #2: it's ok to take the lead

One thing I've learned is that it's surprisingly fun and pleasant to take intitative when it comes to asking a guy out.  Sure, you can do it the old fashioned way and just sit around and wait 'till a guy comes up to you, or you could get off your lazy ass and do it yourself. I'm not saying you should always make the first move, but taking a bold step every once and a while can't hurt.

Surprise yourself by doing something you'd normally never do. You've got nothing to lose.
It's easy. Keep it short, light and clear. Something like "dude, you're great at GTA5, we should play it together some time" (depending on his hobby/interests and the situation of course, but you get the point. Just don't fake a mutual interest). If you get blown off: so be it, it's really not a big deal. And if it's a yes: great! Good for you!

Oh, don't stalk the guy after you asked him. You gave him a chance, if he wants to, he'll take it. It's fine either way. But it's up to him now. The most important thing is to expect nothing. Just go with the flow. You're independent. Stop caring so much before anything has even happened (Most girls go crazy over nothing, I often don't even understand the problem. I mean, you barely know the guy, how can you be so obsessive and dramatic already? On second thought, scratch the 'already': being obsessive and dramatic is never a good thing, but I'll get back to that later).