Was the impossible tasks guy Scott Kim? He's a graphic designer who comes up with "Inversions", words/phrases that can be read in different directions because of symmetry that he either discovers or invents. See his website www.scottkim.com
and poke about. Two years ago,
he performed rounds of "Row row row your boat" by himself, whistling one part and humming the other part, each part temporally out of synch with the other, just like you did in groups in grade school. My brain hurts just thinking about doing it. I fancy myself to be a pretty smart guy, but for a whole weekend I felt like I was the dumbest person in a very big room.
One night at dinner, I was sitting at a table with Richard Hatch, Charlie Randall, Gordon Bean, and John Conway. Conway is a mathematics professor at Princeton, who used to be at Cambridge, where he held a post formerly held by Isaac Newton. He invented the computer game of "Life". His presentation was on the calendar and the pecularities caused by the transition from the Julian to the Gregorian calendar (Shakespeare and Cervantes died on the same date but on different days; Spain, a Catholic country had jumped to the Gregorian calendar, but England, Protestant, had not); at dinner, he taught us an easy way to calculate the day of the week for any given date on the (Gregorian) calendar.