A rare occultation of a star by the Kuiper Belt Object known as Eris was recorded in several stations in Chile and at first glance the data suggest Eris is in fact smaller than Pluto--the albedo of Eris must be higher than predicted.
Sky & Telescope has a good write-up.
Here's a report from one of the observers.
And here's Mike Brown's take on the observation (An observation of the observation).