You might be able to minimize the frequency that the fan spins up by positioning your laptop so that air can circulate under the bottom. Maybe set it on two books spaced apart. Also, avoiding putting it on anything too insulating while using it, like a stack of paper or a pillow, might help. I doubt you bring a pillow with you to class, though. (for some classes at some schools I imagine it wouldn't be a bad idea...)

I used to put my G4 Powerbook on a cookie sheet sometimes. This acted as a giant heat sink and vastly improved its temperature. Are you taking any culinary arts classes?

Kidding aside, there are some fold-up desktop pedestal-type things designed to improve air flow under laptops. That might be an option to help it run a little cooler.