Oops, it doesn't look like 'based day' is a national day..

Other days

ruby

Ruby Day
aloxolt

Aloxolt Day
nail polish

Nail Polish Day
lash

Lash Day
blanket fort

Blanket Fort Day
get funky

Get Funky Day
kiss a brunette

Kiss A Brunette Day
pick me

Pick Me Day
lisp

Lisp Day
hoodie

Hoodie Day