NASA's Deep Impact probe (yes, it was named well before the movie) is on its way to a very close encounter with Comet Tempel 1. It will pass by the comet this summer, taking close-up pictures, and will also release a chunk of copper that will smack into the comet (hence the name). This will excavate a pretty sizable crater, allowing scientists to peer inside a comet, and figure out what lies beneath. Well, really, what it'll do is blast out junk from the comet, and the probe will then analyze the stuff ejected. But they do expect to get images of the crater, too.
Deep Impact is close enough now that it got its first image of the comet. Here it is:
That may not look like much, but the image was taken when DI was still 40 million miles from the comet! It'll cover that distance in about 70 days, for a July 4th impact (scientists swear that's a coincidental date).
When that chunk o' copper hits the comet, it'll dig a pretty big crater. How big? No one knows. So NASA decided to sponsor a contest: guess the size of the crater, and win a custom-made plaque from Ball Aerospace (the company that built DI). You can enter the contest here. One caveat: the answer must be in meters. They might have done it in Imperial units, but you know what they say: give someone 2.54 centimeters and they'll take 1.609 kilometers!