Update: The first images of 21 Lutetia should be broadcast around 3pm EDT. See links or embedded video below.
This Saturday, 10 July at 11:45am (EDT), the European Space Agency will be steaming live video taken as one of their space probes flies within 2000 miles (3200km) of a sizable asteroid named 21 Lutetia. How awesome is that!? So be sure to gather up any family or friends that might be around, and make sure they get a chance to watch!
So how big is 21 Lutetia?
According to this site, it's about 2.57E^15 metric tons and between 80km and 100km wide. Translating that into something we can actually wrap our brains around, that means... it's really big. It's just a notch smaller than some of the largest asteroids in our solar systems's main asteroid belt, 2000 times larger than the Earth's estimated coal reserves, about half the mass of one of Saturn's moons (Hyperion), and we'd need too line up something like 15-25 Lutetias to span the diameter of our own moon.
Phil Plait over at Bad Astronomy has more details, and will be streaming video here. You can also watch directly from the ESA streaming video page here, or the embedded video below.
To learn more about why the Rosetta probe is out in space chasing around asteroids in the first place check out the ESA's Rosetta probe blog, this new article and of course it's wikipedia entry.