Ask HN: I want to work at your company as an intern. How do I approach you?

I am a college student in CS looking to work at a startup this summer. I go to a good college, but few startups recruit through our on campus recruiting system (probably due to the fact that they do not need that many interns). If you were a start up, how would you liked to be approached?

I have experience with a few side projects in Rails, Coffeescript, and other web technologies. Right now, when I find a start up that I want to work for, I try to find a friend who has worked / interned there before and get a referral. But the problem is with start ups I know no one at. I usually try to find a human that I can email and then ask them if they are looking for interns and provide some past side projects I have worked on as proof that I can code. But I find this code approach usually a lot less effective. Is there a better way I can be doing this?

Thanks a bunch in advance!