Is he interested?

There is a guy I like, well, that is a bit of understatement.
Anyway,
I attend a College with primarily male students, I only speak to the males, since they are much easier to get along with than the girls.
So, the guy I like only speaks to guys, apart from myself, we often spend time together (Staying late after college certain days together), and partaking in the same activities.
Most of the time, he will come over and sit with me at lunch, or I will go sit with him, but on the rare occasion when we hang around with different people, I notice him constantly glancing over (Only since I am constantly glancing at him too can I notice this...).
We tease each other a fair bit when we are on our own, and often get playfully competitive with each other.

We have spent time together outside of College once, looking round game shops and stuff. But other than that nothing much.
I'm just wondering if there are any ways to know if he is interested, since I really do like him.

You could ask him on a date.....

Problem is, if he doesn't have feelings for me, I would not want to wreck our friendship.

My girl. I was constantly staring at her and noticing her staring at me. I asked her on a date after only about three weeks of knowing her. What's this guy waiting for?

I was not concerned about wrecking a "friendship". Though we get along so well I was more concerned with making her my girl than anything else so I had to take that gamble... and hey it has been working out.