Through highschool, one of my biology teachers kept a cornsnake as a class pet! It was very cute, and the cornsnake was docile as ever. Lots of learning experiences for those not familiar with snakes, or with a fear of snakes.

I'd think that a diurnal snake might make a better class pet than a nocturnal one, but ball pythons are so cute and sweet that I think they're a good snake to introduce snake-phobes to