[Andy A.]

As an aside, if you ever get the chance, you can use a photo resistor and an oscilloscope and see the rise and fall of the light intensity in a room with fluorescent lights. It's one of those oscilloscope 101 things that you just never forget. I remember thinking how neat it was that this tool was seeing something right in front of me that I couldn't.

As for making you sleepy, I've suspected the same thing. In any case, I've always felt like the light was to blue, and your brain isn't seeing the right frequency of light to make it think that its daytime. Theres nothing like full sunlight.

-Andy A.