Skype with a Scientist for families! Sign up, and provide an email. You'll be matched with a scientist who can help explain/answer your questions.
iNaturalist: Phone App ~ have fun outside! Try to identify birds, bugs, and plants! Make your observations, share with fellow naturalists, and discuss your findings.
~ Links by Topic ~
NASA Kids' Club (younger kids)
Check out the Kids' Club for fun games and to learn more about NASA and space!
NASA Makes their entire media library publicly accessible and copyright free!
Plants Are Cool, Too! (middle school, high school, adults too!)
Ep. 3: Undead zombie flowers of Skunk Cabbage (Skunk cabbage can be seeing now in the midwest!)
Find the entire video series here, Plants Are Cool, too!
SMITHSONIAN NATIONAL MUSEUM OF NATURAL HISTORY
Virtual Tours: NASA Glenn Virtual Tours
(added 3/21): NASA has a bunch of STEM activities that you can do at home with your kids, from the NASA Jet Propulsion Lab.