How do you make friends?

I tend to think about things alot, and recently, with most of my close friends having been eaten by either the move-away monster, the new-full-time-work monster or the relationship monster, I've been wanting to make a new socail circle.

There are a couple of new people i have met lately, through having got a part-time job at a gaming venue, who i could see myself becoming friends with. But i dont know how to transition from "enjoy your company in forced employment environment" to "friend who you see outside of work". Not to mention being hospitality, maybe they are just friendly people and i am reading too much into it / thinking about it too much.

One of the guys in my research group at work has started to ask me to hang out more, go to squash on weekends, go to a gaming thing organised by other uni people. I think this could be a transition from uni-friendquantence to friend.

I have also started to hang out with my brother more, go to his dj gig's etc. And so through him I am begining to make friends with his friends, although forever I think I would think of them as "his friends".

I have been trying to keep in contact with alot of the people I hung out with in undergraduate. I find without the structure of uni, i.e. we need to be around for our next class but are not busy right then so we just chillin on south lawn chattin while we wait etc, we dont have much to talk about. There seems limited reason to remain friends. Its not an easy going, comfortable hanging out, but more of that awkward catchup chit-chat.

That being said, there are a couple of people who i wasnt particularly close to in undergraduate that i have seen a couple of times over the last couple of months who i wouldnt mind hanging out with more. But they often seem busy or are uninterested in hanging out except for fairly specific activities. Its becoming a "friend-for-x-activity" sort of deal, and I wonder how I could change that to just being friends. Im also unsure as to whether or not there is any point.

I remember a sex in the city episode were one of the characters had a booty call she used when she was feeling down, and she tried to make a relationship with him, and in the end they both felt awkward, and so she lost her booty call. Would trying to be closer friends with someone you just see every so often to go out drinking with when you cant have your usual crew be analoguous?

Luckily I have one of my closer friends returning from her trip to America in a few weeks, so at least I can steal her hang out time... although she is coming home to start a new job... DAMN YOU NEW-FULL-TIME-WORK MONSTER!