This is an awesome, and much discussed post from the Planetary Society blog: http://www.planetary.org/blog/article/00001305/
…think to yourself: this is Mars. I’m staring through the eyes of a rover that was only supposed to survive three months, maybe six, possibly a little longer; yet it’s been four Earth years since Spirit landed, and it’s still ticking. That’s probably the number one lesson you can teach your friends from this silly little story: the image came down from Mars only two months ago. Both rovers are still up there, and they’re still working, still studying the surface of Mars for us after all this time.