NASA’s Grail mission is about to launch with destination the Moon.
The Delta II rocket will release two satellites into orbit above the lunar surface that will study the effect of gravitational anomalies on the flight trajectories. This will provide information about the internal density and structure of the Moon. They will also carry cameras to send back stereo 3D pictures of the moon surface.
Countdown is currently 4 minutes and holding.
Update: launch scrubbed for today due to bad weather. There are two launch windows tomorrow but forecast high winds may push the date back further.
When it does happen it will be covered on NASA TV
Update 10-Sep-2011: GRAIL has now launched