Math for all

Today I was on the Greyhound bus passing over the vast heartland of America to get from one place to another relatively cheaply sans car. I sat next to a stoner named Dan who also had a lot of other drugs to sell. (People never offer me drugs, even when they're offering drugs to everyone around me. My face and manner just seem to put them off. This was even true in high school. Is it a hint of my stern and disapproving father coming out?) I was reading about tau-functions and Lax's insights re: integrable systems and Dan took an interest. He asked me, Is that, like, calculus? or is it like about primes? He started explaining to me a question he'd considered that he eventually told me was like the Mobius strip of primes; he also told me his stepsister did math and she'd taken refuge in an insane asylum, using the true sense of asylum -- she needed a break from thinking, you know, thoughts, and numbers, and pressure. I told him I was aware of the danger: history provides us with so many mad mathematician examples. I did not reassure him I was safe.

Dan really likes math: he told me he was into it and either that or linguistics is a field he'd really like to return to. I'm afraid his addictions are too strong to allow that, but one never knows. I've had other conversations like this. At a vegetarian/vegan/punk rock breakfast place I once ended up working through triangulations and Euler's number with another homeless guy who might have been a Wobbly organizer. Part of this is my nature: I am small and nonthreatening and talk with homeless guys now and then, and I'll talk about math with anyone (to a point, and that point does include consideration of personal safety). Now, Dan was into kabbalah and numerology as well as primes and calculus and mobius strips, but he did have an attitude that was refreshingly interested (and he told me several times he wasn't trying to date me and I believed him).

So how could I get that whole Greyhound bus into mathematics for fun? Is is possible?