Why?
This is a question I've been asked about 15 times by coworkers and friends since I posted this, "Why crash something into the moon to check for water? Why does it matter if there's water on the moon?" This sums it up the best:

Finding ice on the moon could be critical to future exploration or even colonization. With unlimited solar power, ice can be converted into water, oxygen, and hydrogen rocket fuel. Finding ice on the moon also would raise the possibility of similar deposits in similar environments across the solar system.

I have a question; if a rocket hits the moon at 5600 MPH (7 times the speed of sound) and creates an explosion equal to 1.5 tons of TNT, will it make a sound? I know very little about sound except it requires air (of some kind, not necessarily breathable) to travel on ... I do know that I would love to find out.

I'm a pacifist by heart, but, unlike these folks, I like explosions ... when they aren't killing anything. On Friday, October 9, at approximately 6:15am (US EST / 6:15pm China), NASA's LCROSS satellite will shoot a rocket at the moon's southern pole to see if there is water under the surface. This will be broadcast on NASA TV, and I'll be giving up a couple hours of precious sleep to watch it.

I just hope it's a little more spectacular than this animation ... and I hope the music isn't so craptastic.

UPDATE
Well, I didn't make it out of bed in time to see the LCROSS impact, but I don't think I missed much. I was expecting to see pictures/movies from ground based satellites, not a nose cam from the projectile itself. The projectile's nose cam, obviously, stops transmitting as it hits the surface of the moon, which is kind of pointless for people looking for a big explosion. Anyway, here's a video plus some commentary of the event (Warning: It'll put you to sleep.)