In the spirit of Saint Patrick’s Day, March 17 of every year…
In the spirit of Cinco de Mayo, May 5th of every year…
May the 4th, Star Wars fiction science every year…

April 20 of every year, 4/20. A science-themed holiday. Science contests and demonstrations? Favorite non-fiction science films and TV series (Cosmos?)? Lab equipment of science to make bongs? Recruit children to learn and study science and the joy of learning?

Carl Sagan also was a supporter of weed, Mr. X: https://www.theguardian.com/science/1999/aug/24/spaceexploration

Can we make this a thing?!