It was a spectacular sight last night. Shortly after sunset a thin crescent moon was visible with the dark side illuminated by earthshine, i.e., sunlight reflected off the earth onto the moon and back again. Just a few degrees away was Jupiter. There was little time to think about how to take the photographs correctly so just snapped away and hoped I'd get something.
This is something you can only see for a few hours each month. It has to be close to a new moon to see earthshine and the new moon won't do it since it'll rise and set with the sun. During the day the sky is too bright to see the dimly lit dark side of the moon but for an hour or two after sunset (or just before sunrise - it depends whether the moon is waxing or waning) the moon looks very different.
You need a clear sky as well of course!