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

Other days

hot chocolate

Hot Chocolate Day
get funky

Get Funky Day
ruby

Ruby Day
nae nae

Nae Nae Day
lumpy rug

Lumpy Rug Day
kiss a ginger

Kiss A Ginger Day
ride the wind

Ride The Wind Day
gum

Gum Day
hiv awareness

Hiv Awareness Day
cuddle up

Cuddle Up Day