Anthony Watts sets the standard with the title of his blog post: Paleo-clamatology.
Clever Canuck limnologists have figured out how to analyze growth rings in clam shells for oxygen isotopes tied to water temperature. Graphed out on a 2500 year scale, the results show the typical signatures of the Roman Warming Period, the Medieval Warming Period and the Little Ice Age.
Not that anyone in this room is surprised. It's just nice to see it confirmed in an independent data set.
Maybe this will encourage some of the MWP deniers to, ooh, clam up!