Tonight is a total lunar eclipse. These aren't very rare, and there isn't much science to be done, but they can be beautiful, and tonight's is predicted to be a good one. The Earth's shadow is already visible across the moon, I took the photo shown here at about 2125GMT.
At totality, between 2244 and 2358 GMT, the only light which reaches the moon will be that which has refracted and bent through the Earth's atmosphere. As the Earth's atmosphere scatters the blue end of the visible spectrum (hence blue sky) what's left is the red end. This means that the moon will have a red hue. The exact colour will depend upon all sorts of factors, pollutants and weather for example.
More poetically, when you look at the moon tonight you will be seeing all the sunsets and all the sunrises simultaneously.
UPDATE: This photo was taken at about 2151GMT.