I would recommend talking to someone with some basic lighting experience. It?s worth its weight in gold to get some direct advice on your problem -- and lighting is as much an art as a science.

That said, here is a good web article that describes some basic cheap lighting:

http://directory.filmjumper.com/article.php?n=2

Also, check out lighting basics (3 point lighting) here:

http://www.andrew-whitehurst.net/3point.html

Note that there is something called Light Temperature. To boil it down, all light has a dominant color. Simplified: daylight is blue while most light bulbs (generally called tungsten) are yellow/orange. Fluorescent lights have a green tinge. If you mix and match, your camera can?t color balance/white balance properly and most things will look wrong.

Unless you can turn off the fluorescent lights and use your own tungsten lights (which might include standard bulbs, a Home Depot 500W work light, etc.), you?ll have to stick with fluorescent lights to make sure your color balance isn?t terrible.

Problem is, you want to get rid of that dull/flat fluorescent look. The only thing I can think of off hand is to use a tungsten rim light (see 3 point lighting page above). The yellowish color could look like sun shining in a window and might produce an appealing effect.

Hope this helps.

Dan Rahmel
Author: "Nuts and Bolts Filmmaking"
http://www.cvisual.com

This probably isn't what you're looking for, but:

You might just want to go with it. Simple extra lighting, such as lights coming in through windows (if the room has windows) might be nice... But one of the things I think when I think of classrooms, is flourecent lights. It might be an interesting contrast to the lighting throughout the rest of the film.