From SpaceWeather.com:

Tonight’s full moon has a special name–the “Harvest Moon.” It is the full moon closest to the northern autumnal equinox. Long ago, before electric lights, farmers relied on the Harvest Moon to light up their fields at night, allowing them to harvest autumn crops even after sunset.

The Harvest Moon of 2006 is a big one–almost 12% wider than some full Moons we’ve seen earlier this year. Why? Because the Moon is near perigee, the side of the Moon’s lopsided orbit that comes closest to Earth.

When the Harvest Moon rises tonight, go outside and look around. You might see some strange things.

Check out that second link for some very interesting tidbits about moonlight and how it changes the way we see things.