This is kind of incredible, in the best way. ESA's cometary lander put down on Comet 67P in November 2014. It transmitted for two and a half days and went silent, its batteries run down, its body-mounted solar cells presumably shaded by terrain and unable to recharge it. As the comet approached the Sun, though, solar energy (direct or reflected) on the cells increased enough to wake up the spunky little 100-kg spacecraft and prompt it to transmit an electronic "hello." Indeed, it turns out the lander has considerable information in its memory queue and must have been actively gathering data at some point during the long silence.
Congratulations to the ESA team. A space first - the landing of a probe on a comet - has become even more memorable.