When Mars Science Laboratory (MSL) Curiosity performs its entry, descent and landing (EDL) sequence, it will be 7 minutes of terror.
"EDL is referred to as the 7 minutes of terror because we've got literally 7 minutes to get from the top of the atmosphere to the surface of Mars. Going from 13000 miles per hour to 0, in perfect sequence, perfect choreography, perfect timing... If any one things doesn't work just right it's game over" - Tim Revellini, EDL Engineer for MSL Curiosity.
Below is the NASA/JPL video about landing Curiosity on Mars. Touchdown is anticipated at 0131 ET on 6 Aug 2012!