Cripes, I'm getting behinderer every day, so I missed posting about this: The 100 Hours of Astronomy effort began yesterday! It's a cornerstone project of IYA, to do 100 continuous hours of astronomy-related observations or activities.
For example, telescopes all over the planet are observing the skies and webcasting it all live.
There are star parties all around the world; Popular Mechanics has an alphabetical list of the ones in the US.
Even space probes are in on it; the Cassini Saturn probe team posted their favorite Saturn images on their site in honor of Galileo.
100 Hours was honored in an APOD image, too.