Hey there,
Saw you texted me about this, good stuff.
You're starting to turn away from being the "funny" guy and start being the "fun" guy. This is good. As much as the funny guy gets girls to laugh and smile, the funny guy simply does not get laid. Who wants to sleep with a clown? No one

- The fact that you just chilled out and hung out with your friends is really important. To have friends of the opposite sex is a great way to social proof yourself and to just have a good time with those people. I have my own group of girls that I do not sleep with, nor ever kiss, but we hang out and grab lunch, or go do cool things together like SCUBA dive or surf.
When you're in a social circle setting like this, it's great to just hang out and chill. Don't worry about game, what stupid routine you're going to do next, or how you're going to open girl XYZ. The art of being Cool - as noted by Gareth - is to not try to be cool. It's as simple as that.
On the other hand, to be the most interesting person in the room-
1. Do a bunch of stupid shit
2. Love to talk about yourself
For the next step, I feel like you should concentrate on being a really interesting person and show it in a way that doesn't seem try-hard or "tough as nails." Have fun with it, you've got a whole summer ahead of you to explore and try new things. One of my favorite blogs is LifeHacker. Go try out some of the stuff they have on there and let us know how it goes!
Ben J