I work at a newly-minted startup of five people.  We have a Ph. D in machine learning, a former member of the RSpec core team, and the guy who compiles the Git binary for OS X.  That's just the employees; the founder has a Ph. D and was CTO for a multi-billion-dollar corporation before leaving to start a (successful) startup, and has now left that to start this one.  We also might get a guy with a Ph. D in math.

Aaaaaaaaand then there's me, college-dropout intern.  I think I'm pretty smart and I'm reading non-stop, but the delta of experience, skill, and knowledge between me and my co-workers is just breathtaking.

So put yourself in their shoes: you've got a bright young intern who has a lot to learn but is at least energetic.  What would be annoying?  What use would you hope to get out of him in the here and now?  What would be pleasantly surprising if it happened?

Most important thing:

Don't be impressed by the titles. In a short time, you will realize that your Ph. D coworkers, too, are just humans. And some people with a Ph. D never really created anything practically usefull. Always remember that, don't feel inferior.

What I'd expect of you?
To write good code and get things done. Chances are that you are someone who is really working, as you describe yourself as energetic. I've seen lots of people with degrees who took like forever to achieve simple tasks because they were focussing too much on details etc. Put that to good use and deliver good code in a reasonable time and soon everyone will respect you.

But don't disrespect the others. They're most likely older and you can probably learn valuable things from them. But don't take anything over mindlessly. Always try to understand and think for yourself. I'd expect you to copy the behaviours and knowledge from them that really work.
