“My first day, I hardly knew a soul and had no idea what events were happening around me,” he recalls. “One would have really helped, as it gives you more information about the people and things happening around you based on your interests.”

Available for iOS, the app was meant for the college set. One notifies people of other nearby users, called “matches,” based on location and shared interests, like an affinity for Daft Punk or Lord of the Rings. Available at four schools, including the University of Illinois, Levy and Callahan will introduce it to at least 10 other schools by fall thanks to nearly $2 million in seed funding from Ron Conway, Keith Rabois, True Ventures, and other backers.

But before that happens, Levy, 21, and Callahan, 29, will vie as one of five contestants for the mantle of this year’s Startup Idol competition at Fortune’s Brainstorm Tech conference, at the Aspen Institute in Colorado. We caught up with Levy beforehand for a few quick questions.

Q: Let’s pretend it’s next week already, and you’re onstage. Give us your elevator pitch in one sentence.

A: One is a mobile application that notifies you when someone is right next to you who shares a number of rare things in common.

There are other so-called people discovery apps out there that may have somewhat different aims but the same underlying principle. (Take Highlight, for example.) So how is One different?

So if I were talking about “people discovery,” I would contrast it and say with Highlight, what you do is very passive. It’ll tell you if someone is a couple blocks or a few miles away. We see that as “non-actionable” information.” Who cares if someone is a couple miles from you or a couple blocks from you? You’re not going to walk a long distance to go meet a stranger. But if you’re sitting in a class or at a restaurant, and there’s someone right next to you with a number of rare interests in common, the chances of you actually connecting with that person increases. No one’s been able to get that range of accuracy, and we like to say that that in itself is a sort of technical achievement — our proximity engine — that allows someone to connect when they’re three feet or 20 feet from each other.

Secondly, we’re building a product for ourselves. This is a product geared towards college kids. We know what we want and what our friends want. We’re closer to the problem compared with other founders who may be a little bit older.

Technically, this Brainstorm Tech conference isn’t your first. You gate-crashed one year, right?

Three years ago before we even started work on One. I was in Colorado on a family vacation, and I noticed when I was walking the street that there were these nice cars driving around with “Fortune Brainstorm Tech” signs. So I hopped into one, and I said, “Yep, take me there,” or whatever. I wasn’t signed up or anything, but I was driven into the venue. Actually, I snuck in and sat next to Keith [Rabois]. I connected with him. Fast-forward, he became our first investor. Of course, I got caught eventually, but I convinced Fortune to give me a ticket for the last two days or so!