Those two Mars rovers, named Spirit and Opportunity, landed on the red planet in January 2004 and are still going strong, twelve times longer than their originally-planned mission of 90 Martian days. Together they've sent more than 160,000 images back to Earth and have driven a combined 10.4 miles.
The two rovers were pretty much chowderheads when they first landed, but now they're quite a bit smarter because of their newly-uploaded software. Now they can be more picky about their choice of snapshots, recognizing that, for example, a rock they're looking at is the same one they saw earlier, but just from a different angle. This keeps the little robots from taking multiple pictures of the same thing.
Perhaps scientists will teach them how to reproduce, and then an entire population of the little droids will be there to meet their earthling overlords if we ever arrive.