TED
TED is, in effect, a convention of speakers from various walks of life, generally predisposed towards science, arts, and humanities. Run by a small non-profit group, it attracts many of the biggest names in three industries: Technology, Entertainment, and Design. Biyearly conferences occur in various locales, including Oxford, Tanzania, and Mysore, attracting presenters from all over the world - though the central, annual convention is still held in Long Beach, California. Each "talk" runs a variable amount of time, from five minutes to almost an hour, and the most well-received presentations are provided for free viewing online, under the Creative Commons license.
Talks generally range from the arts to the social sciences, from new methods of interactive design to discourse on education systems. The tone of the presentations oftentimes ranges towards the irreverent, humor and jokes interspersed throughout.
The organization also hosts a charity, the "TED Prize", a $100,000 USD grant and assistance provided yearly to three individuals who wish 'to change the world' in a tangible, worthwhile manner. Every year, after months of preparation, these three individuals release their idea publicly, at the central talks in Long Beach.
TED's website can be found here, but be warned: while worth watching, the videos contained can quickly lead to an Archive Binge. Many TED Talks are also to be found on YouTube.