Lucky enough to catch a public lecture by Kip Thorne. One of those rare people who can make the mysteries of modern physics understandable and very entertaining, the part about the bet he won with Steven Hawkings over naked singularities got a few good laughs.
Kip's current work on gravitational waves on the practical side led him to talking about LIGOS, several of these instruments are currently up and running. The instruments are an optical interferometer that bounces light off mirrors 4KMs apart. They're measuring the distance between the mirrors to an accuracy of 10^-16 cms , within a year ot two they hope to increase the accuracy by another order of magnitude. To attempt to get a handle on that kind of accuracy it's around 1 10,000th the diameter of an atomic nucleus.

I was a bit taken aback to learn that the GRG 18 conference was being sponsored by BHP Billiton, what has any of this got to do with a mining company. Well thanks to this kind of work BHP were able to develop a working gravitational gradiometer. With this device in an aircraft oil, diamond etc can be searched for by looking for the way they affect the earth's gravitational field.
See here for details.

If anyone would like to help with the search for gravity waves you can download einstein@home from here.