http://www.ted.com/speakers/stephen_petranek.html
The punch line of this is that while the talk we watched was about 10 things to be optimistic about, the only one he has online is on the 10 ways the world might end.
TEDxNewYork is held at GreyNY, 200 Fifth Avenue. We meet every week (mostly) on Fridays now and (mostly) from 1-2pm. We are open to the public. If you want to attend, send a note to admin@tedxnewyork.com (that's Don McKinney & Chel O'Reilly) with your vitals. Our biggest limitation is space so give us plenty of notice and we'll do our best to accommodate. Hope to see you at one of our events soon.