The National Science Foundation’s Multimedia Gallery features nearly 100 videos and webcasts on a wide range of science topics, including a fossil that might represent the first vertebrate to emerge from the sea; turning forest-industry waste into fuel and textiles; "superglue" produced by aquatic bacteria; a house built on a "shake table" (earthquake research); teaching robots to swim; 14 engineering challenges for the 21st century; solving a crime scene mystery; a 60-second history of the universe; earth’s deep-time archives; dinosaurs; and more. The video clips are searchable by keyword or phrase.
http://nsf.gov/news/mmg/index.cfm?s=2