TED stands for Technology, Entertainment, Design. It started out (in 1984) as a conference bringing together people from those three worlds. Since then its scope has become ever broader.
TED has an annual TED conference, where they invite visionaries to talk about things that interest them, topics ranging from microbiology to design. Some of these talks come out as TED Talks, available online. They also have an annual TED Prize, given to one of the speakers, which comprises $100 000 and one wish to change the world, basically giving the people an opportunity to use TED to promote their agenda.