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

Other days

slime

Slime Day
girl friend

Girl Friend Day
brow

Brow Day
unicorn

Unicorn Day
boy friend

Boy Friend Day
artists

Artists Day
aloxolt

Aloxolt Day
kiss a brunette

Kiss A Brunette Day
gallery

Gallery Day
healing

Healing Day