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

Other days

blanket fort

Blanket Fort Day
slime

Slime Day
lash

Lash Day
ride the wind

Ride The Wind Day
cuddle up

Cuddle Up Day
ormille

Ormille Day
tulip

Tulip Day
pumpkin

Pumpkin Day
pick me

Pick Me Day
believe

Believe Day