Ice on Mars!
A few days ago, the Mars Phoenix robot (now communicating with us directly from mars) uncovered some unknown white patches. Yesterday it was discovered that it disappeared. According to the scientist folk over at NASA, that means those white patches must've been ice, which dissipated after being uncovered. Now Mars Phoenix still has the considerable task of uncovering more ice and sampling it, but the mission is ahead of schedule and NASA has already identified a hard patch of ground it wants to dig into. I'm confident that they will be able to confirm more ice on mars, but I'm not really sure how that helps us. Nevertheless, it is very interesting.
You can read more about this at the wired article that brought this to my attention.
I can't wait to go sledding on mars. :-)