NASA - their entire media (images, sounds, and video) library is publicly accessible and copyright free. Students get an opportunity to see stunning images of outer space. Additionally, there are also images of astronauts, rocket launches, events at NASA and other interesting stuff.
National Geographic for Kids - offers a ton of videos and activities for many many topics.
Virtual Field Trips - over 30 Virtual Field Trips including San Diego Zoo, Mars, Animal Cameras, and Yellowstone.
Scholastic - Provides day to day projects to keep kids reading, learning, and thinking through 9th grade. Provides 20 days of articles and stories (can be read using built-in speech synthesis), videos, and fun learning challenges. Children can complete them anytime, in any order.
Boardmaker Activities - free, downloadable, printable activities for students in K-12. Designed for parents, educators, speech language pathologists, behavior specialists, and others across home, school, and clinic settings. Includes three levels of materials for students from beginners to those who are working on developing some independent skills.
Boardmaker Online - sign-up for a 30-day free license to Boardmaker Online to use an entire collection of ready-made, online lessons including the comprehensive English Language Arts program called Reading Avenue.
Kansas State Library - serves the library needs of Kansas citizens and provides access to high-quality online resources.