Curiosity, more formally known as the Mars Science Laboratory, will be attempting to land on Mars on Sunday, August 5th, at 10:31 PM PDT. They are using that time zone because the JPL Labs running the rover are based in California. I think the landing is going to be pretty exciting (referred to as the Seven Minutes of Terror by the NASA scientists behind the mission), and if you like you will be able to watch live coverage as it happens. To give you an idea of the landing process, watch either of these videos.