Interestingly, it is actually possible to see the Moon's surface during an eclipse. Normally we don't because the contrast is so great, but these photos show what's hidden in the glare (not by me, but by someone very enterprising, described in the second link:
http://www.digitalsky.org.uk/solar/t...arthshine.html
http://www.astronomyforum.net/uk-ast...arthshine.html
Earthshine, or "the old moon in the new Moon's arms", (the glow of the Earth illuminating the otherwise night-time face of the Moon) is commonly visible when the moon is a crescent. It's at it's brightest at New Moon, when Earth is full in the sky of the darkened near side of the Moon, we normally don't see much of it because the moon is too near the Sun...