The TED Talks are the cornerstone of the TED organization, a non-profit whose name stands for "Technology, Entertainment, and Design". They bring together people who have, as they put it, "Ideas Worth Spreading" and put their talks online. These ideas range from social causes to science and technology.
They're definitely good to watch and attention-grabbing, as you might expect from hearing people who're talking about what they are most passionate about.
One of my favourite videos which isn't on the list is David Gallo's show-and-tell of "Underwater Astonishments", ranging from deep-sea bioluminescent patterns (Edith Widder, who took the these videos, has a talk of her own) to the clever and changeable world of cephalopods (squid and octopods):
The TED concept has also spread to different countries and cities with the TEDx series, which are TED events organized by independent organizations. In Singapore there's TEDxSingapore, TEDxNTU, and TEDxNUS. The Biology Refugia's own Sivasothi gave a talk about protecting biodiversity in Singapore for TEDxNUS:
In another video, graduate student Ang Yuchen explains his research on insect sexual selection:
Plenty more videos on all manner of subjects are available on the TED website. So instead of listening to yet another music video or watching cute kittens play with string on YouTube, why not check some of them out instead? You'll definitely learn something new!