Check out James Thornton’s Theory of the Week site. It hasn’t been updated in over a year, but when it was operative, each entry featured a brief description of some theory, principle, or concept. Some of the items covered are Occam’s Razor, the Gaia Hypothesis, the Butterfly Effect, and the Peter Principle. As far as I can tell, there are only 30 entries, though others might be archived somewhere. But what a great idea! We should encourage this guy to start the site up again. Maybe he just needs more ideas for theories to include.