MandarisI’ll have to mark this off for next year.
Tau Day is a celebration of the circle constant 𝜏=𝐶/𝑟= 6.283185… Founded in 2010 with the publication of [_The Tau Manifesto_](https://tauday.com/tau-manifesto) by [Michael Hartl](https://www.michaelhartl.com/), Tau Day takes place annually on June 28 (6/28 in the American calendar system).
Found via Spaf on Mastodon.