Anti-aging expert Aubrey de Grey came through Big Think Friday afternoon looking not a bit older than when he first appeared on our site, in December 2007. He was in New York for the two-day Singularity Summit at the 92nd Street Y.  We interviewed him for an hour and then joined him for a pre-singularity soiree that lasted until early this morning.  Among the many reasons he gave for devoting his career to defeating aging was a sobering economic one: in the last year of our lives, Americans spend as much on medical care as they spend on doctors in all the years up to then combined.