At www.abc.net.au/science/articles/2011/07/25/3274891.htm (and many other blogs around the world) there is a report on the discovery of a volcano hotspot on the far side of the Moon (source being the journal Nature Geoscience) which came about as a result of images taken by NASAs Lunar Reconnaissance Orbiter. The volcanic activity took place millions of years ago – 800 million years ago according to ABC. This is of course an estimate basied on consensus thinking of the Moon's geology and origin. The same point emerges in comments on a piece on the same news report at http://wattsupwiththat.com/2011/07/25/volcano-found-on-the-moons-farside/ but the important point is that the volcanic activity took place long after the Moon's attachment to the orbit of the Earth and there must be a reason beyond solar system dynamics for such an eruption or hotspot. We can expect minds to juggle around with possibilities in the course of time.
Meanwhile, at www.physorg.com/print225628957.html we learn that the interior of the Moon contains as much water as Earth's upper mantle. Note – mantle, not crust.