There is supposed to be a Lunar eclipse tonight, and for once, although the forecast calls for increasing clouds this evening, the sky may actually be clear enough to see it. That's the good news - the bad news is that it's going to be a Penumbral Eclipse, so you may not notice.
Here's what a penumbral eclipse looked like in 2002:
Eclipses of the moon fall into three categories - total, partial and prenumbral. In a penumbral lunar eclipse, only the more diffuse outer shadow of Earth falls on the moon’s face.
This third kind of lunar eclipse is much more subtle, and much more difficult to observe, than either a total or partial eclipse of the moon. There is never a dark bite taken out of the moon, as in a partial eclipse. The eclipse never progresses to reach the dramatic minutes of totality. At best, at mid-eclipse, very observant people will notice a dark shading on the moon’s face.