A demo of Myngle, the worldwide languages marketplace, where teachers and students from all over the world can mingle and learn a new language, having fun!

Watch as Jeff Howe, author of Crowdsourcing: Why the Power of the Crowd is Driving the Future of Business, explains how online communities are changing the way many companies do business.

Designer Yves Behar digs up his creative roots to discuss some of the iconic objects he's created (the Leaf lamp, the Jawbone headset). Then he turns to the witty, surprising, elegant objects he's working on now -- including the "$100 laptop."

Benjamin Zander has two infectious passions: classical music, and helping us all realize our untapped love for it -- and by extension, our untapped love for all new possibilities, new experiences, new connections.

With stunning photos and stories, National Geographic Explorer Wade Davis celebrates the extraordinary diversity of the world's indigenous cultures, which are disappearing from the planet at an alarming rate.

In this brand-new slideshow (premiering on TED.com), Al Gore presents evidence that the pace of climate change may be even worse than scientists recently predicted. He challenges us to act.

In an emotionally charged talk, MacArthur-winning activist Majora Carter details her fight for environmental justice in the South Bronx -- and shows how minority neighborhoods suffer most from flawed urban policy.

Jill Bolte Taylor got a research opportunity few brain scientists would wish for: she had a massive stroke, and watched as her brain functions -- motion, speech, self-awareness –- shut down one by one. An astonishing story.

You've never seen data presented like this. With the drama and urgency of a sportscaster, statistics guru Hans Rosling debunks myths about the so-called "developing world."

Dan Gilbert, author of Stumbling on Happiness, challenges the idea that we'll be miserable if we don't get what we want. Our "psychological immune system" lets us feel truly happy even when things don't go as planned.

Blaise Aguera y Arcas leads a dazzling demo of Photosynth, software that could transform the way we look at digital images. Using still photos culled from the Web, Photosynth builds breathtaking dreamscapes and lets us navigate them.

Barack Obama talks in Spanish about the American dream. This video is unique in the history of presidential elections: No presidential candidate has ever recorded such a long video in the language of Cervantes. Open to translation in other languages.