I only realised yesterday that the rovers Spirit and Opportunity have been on Mars for over five years now and they are both still working and sending data! Considering the murderous radiation exposure and temperature swings, this achievement is absolutely mindboggling. I have never had a mobile phone that lasted so long in the relatively clement conditions on planet Earth. (While terrestrial goods are designed to break down after the end of the 6-month guarantee, the Mars rovers were anticipated to survive for just 90 days!)
Here's a NASA press release celebrating the occasion, and a recent feature from the Observer.