On their website you can choose a theme from a long list and then find talks arranged by title and speaker. One theme that caught my eye was "Design Like You Give a Damn", featuring talks by such notables as Dean Kamen (Segway creator), William McDonough (author of 'Cradle to Cradle'), Marian Bantjes (graphic designer), and Paola Antonelli (design curator at MoMA), plus lots of others I didn't know of. Another theme that piqued my interest was "Food Matters" featuring some usual suspects such as Jamie Oliver on kids' lunches, Mark Bittman (minimalist chef), Michael Pollan (organic growing), as well as the intellectually peripatetic Malcolm Gladwell ('The Tipping Point'). There are themes for and about women; themes devoted to happiness, evolution, medicine, comedy, war and peace, poverty, and storytelling, to mention but a few- lots of brain nutrition, humor, and even some live music.
On www.ted.com be prepared to spend many mind-opening hours exploring this site, if you're like me and still curious after all these years.