[AllenG (OP)]

I heard about this today and found it absolutely amazing.

http://news.bbc.co.uk/1/hi/sci/tech/7780873.stm

It has been described as a geologist's dream - a unique opportunity to study up close the volcanic processes that built the Earth's continents.
Drillers looking for geothermal energy in Hawaii have inadvertently put a well right into a magma chamber.
Molten rock pushed back up the borehole several metres before solidifying, making it perfectly safe to study.
Magma specialist Bruce Marsh says it will allow scientists to observe directly how granites are made.
"This is unprecedented; this is the first time a magma has been found in its natural habitat," the Johns Hopkins University, Baltimore, professor told BBC News.
"Before, all we had to deal with were lava flows; but they are the end of a magma's life. They're lying there on the surface, they've de-gassed. It's not the natural habitat.

"It's the difference between looking at dinosaur bones in a museum and seeing a real, living dinosaur roaming out in the field."