If you live in a severely light-polluted area like me, here's something we can do to help quantify it:
Join thousands of other students, families, and educators by participating in GLOBE at Night—an international event designed to observe and record the visible stars as a means of measuring light pollution in a given location. Participation is open to anyone—anywhere in the world—who can get outside and look skyward during the week of March 22-29, 2006! There is no cost to participate in GLOBE at Night. Help us reach our goal of 5000 observations from around the world!
I reckon it would take me about a minute to count all the stars I can see in Orion from my backyard—all ten of them. Sigh.