Math
Math-Kitecture
http://www.math-kitecture.com/index.htm - Math-Kitecture provides a basic step-by-step lesson plan for creating a floorplan of the classroom (from sketching to scale drawing to computer-aided drafting). Also includes activity ideas for finding geometry in architecture and 3-D graphics of Frank Lloyd Wright’s Fallingwater.
MoMath
https://momath.org/ - MoMath, the National Museum of Mathematics, is an award-winning museum that highlights the role of mathematics in illuminating the patterns and structures all around us. Its dynamic exhibits, galleries, and programs are designed to stimulate inquiry, spark curiosity, and reveal the wonders of mathematics. The Museum’s innovative exhibits will engage visitors of every age, from 1 to 100! Free online sessions are available for all age groups.
NYU Center for Mathematical Talent (NYU CMT)
https://cims.nyu.edu/cmt/activitiesOverview.html - Math activities for all ages are available. Math activities include: Play One Row Nim, One Piece Chess, The Fifteen Game, Magic Squares, and 3-Dimensional Tic Tac Toe.
MishMash of stuff
https://www.thewalkingclassroom.org/ - The mission of The Walking Classroom is to help strengthen the physical, mental, and academic health of children. The program teaches children to establish and maintain healthy lifestyle habits, while also building their health literacy and core content knowledge. Students walk, listen, and learn. Activities target youth in grades 3 through 8.
Bedtime Math
http://bedtimemath.org/splash-of-math/ - Several lesson plans to support in nonscreen time mathematics learning.
Harry Potter at Home Digital HUB
http://harrypotterathome.com – The Harry Potter at Home Digital Hub has all kinds of activities to keep youth occupied including videos, articles, quizzes and puzzles. Great for elementary school age youth.