The Mars Rover Curiosity Lego set actually has an interesting back story. Its designer, listed as Perijove on the set's official Cuusoo page, is a mechanical engineer who worked on the real Mars Rover Curiosity at the Jet Propulsion Laboratory, which means his recreation of the rover is highly accurate, not only in how it looks, but also in the details and all of its moving parts. Perijove states that the purpose of his model is "to continue the educational outreach for this incredible mission." The timing couldn't have been better, as the set became popular on the Lego Cuusoo site in late Summer 2012 when the real Curiosity rover touched down and began rolling around on the surface of Mars.
The last set to make it all of the way through Lego's Cuusoo program was the Lego Back to the Future DeLorean, which received approval for production last December. Other autos-related Cuusoo sets that received 10,000+ votes and are scheduled for production review include an incredibly detailed Land Rover Defender 110 and minifig-scale Batman Tumblr.