The Mars Science Laboratory (Curiosity) of NASA/JPL is going to land on Mars this coming August 5, 2012, on 22:31 Pacific time. Check out: http://mars.jpl.nasa.gov/
Watch the video "7 Minutes of Terror" and you will picture the complexity and the challenges of the engineering involved.
I'm so excited and proud to be part of it.
This is a picture of our team (among other teams) where all 3 generations of rovers were on display. I'm fortunate to work on 2 of them: the medium size Mars Exploration Rover (launched 2003) and the large size Curiosity (Mars Science Laboratory, launched 2010). The smallest one is Sojouner (Mars Pathfinder, launched 1997).