I live in a very very very religious area. Mostly mormon, but with a healthy smattering of christians of several flavors.
Anyways here are a few things that actually happened to me in school.
In science the teacher had us sort ourselves out by different characteristics. Eye color, hair color, birthdate, and finally. Religion. Knowing I was in a heavily religious group I walked off on my own to stand by myself. As I thought, I was the only Atheist in the class. A boy in the group nearest me, Catholics actually, looked over and asked me. "Why are you standing by yourself? What are you?" I replied, "I'm an Athiest." and to this he says "You worship the Devil!!!" I tried to explain to him that I was not a Satanist, but in fact did not believe in the Devil either. He apparently found this hard to accept and never spoke to me again.
One day in English, while debating some story, I can't quite remember which, the teacher brought up an allusion to the bible. We discussed back and forth and debated. Mostly between myself and a girl in front of me, Autumn (Who was actually a Wiccan) argued for Christianity, while I argued against. Then we actually reversed positions at one point where I argued the merits of one particular allusion while she argued against it. I personally enjoyed the debate immensely but apparently the Atheist and Wiccan knew much more about Christianity than all the Christians in the class. Afterwards the girl behind me asked what religion I was and I of course answered honestly that I was an Atheist. She said "What's that?" I told her that it meant I did not believe in a higher power. She apparently could not wrap her head around the concept. Hearing this a boy nearby said, "Even if you won't admit it you believe in a higher power. Everyone does." I told him "No really, I don't." he would not accept that such a fram of mind was even possible. Unlike the one from science class this boy decided to spend the rest of year trying to convert me.
The Science class was junior year in Highschool. The English example was freshman english.