First you need an object (or subject - if you have a willing participant...) Throw your camera in M and start with an ISO of 200 and an aperture of f4.0. Put the object (or subject) right beside a north facing window. Meter for the light side and take your first shot. Move your object (or subject) about 2 feet away from the window, meter for the light side, and take your second shot. Repeat at 2 feet intervals until you've run out of space in your room. Repeat with a west or south facing window. If the day you shoot is overcast, you might want to try it again on a sunny day, and while you're at it, try out the Sunny 16 rule ;)
While shooting, take note of how the Law of Reciprocity affects your settings change as you move away from your window light. How far away do you get before your shutter speed drops below 1/60? Did you have to bump your ISO?
When you get your pictures on your computer, check out the quality of the light between your exposures - how hard or soft are the shadows? Are the shadows harder from the north or south window? Which side do you prefer? How far from the window is the "sweet spot" for you?
Send me a link when you're done!