The Curiosity rover comes complete with a mini chemistry lab. It's designed to analyze the composition of Martian soils and Martian air. And, right now, that particular piece of equipment is at the center of a giddy storm of activity. Curiosity has turned up something important — big enough for Curiosity's principal investigator to tell NPR, "This data is gonna be one for the history books."
What is it? NASA's not telling just yet. Right now, researchers are in the process of verifying said exciting data, in order to make sure they aren't deceiving themselves into thinking they've spotted something that isn't really there. That's pretty good policy, given the recent flap around over-hyped studies about Earth-like planets and arsenic-based life.
On the other hand, if you're trying to avoid overhyping something, might I suggest that "We have groundbreaking, world-changing data that we can't tell you about yet," is maybe not the best way to do it.
Pictured: A 360-degree view of Mars, taken by Curiosity on October 5th, from the location where it first started collecting samples of rocks and dirt. NASA/JPL