I found this question, just like last week's, on a job interview help site, though I'm tweaking it a little. It asked 'in the past year' and I made it more broad.
What was a major obstacle you were able to overcome in your life?
Never let your memories be greater than your dreams. ~Doug Ivester
Picture from wikipedia. I don't really know how to attribute this pictures, so here's where to find the info on it: http://en.wikipedia.org/wiki/File:Ferguson-slide.jpg