Asteroid Day "is the United Nations sanctioned day of public awareness of the risks of asteroid impacts" [0] though in practice, it's a pretty fun day of learning about asteroids through local events and even 24 hours of streamed programming on Twitch and YouTube. [1]

The current incarnation of Asteroid Day seems to be a push by a group of scientists and filmmakers, among them astrophysicist Dr. Brian May, and more aimed at celebrating asteroids and their role in the solar system.

[0] https://asteroidday.org/about

[1] https://www.youtube.com/asteroidday