"Curiosity" launches Saturday morning 10:02am EST / 15:02 UST
This is a nearly 1 ton Mars probe.
NASA Tv has been running info on it, and of course will cover the launch of the Atlas V lifter.
NASA/JPL UStream channel. will be broadcasting the lunch as well.
Fingers crossed.
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Due to the size I won't post the picture of the rover in this post, but here's a link to it if you want to see it.
http://www.nasa.gov/images/content/605805main_msl_lab_workersandrover.jpg