Oops, it doesn't look like 'boy am i single day' is a national day..

Other days

offer

Offer Day
buddy

Buddy Day
girl friend

Girl Friend Day
believe

Believe Day
tell a fairytale

Tell A Fairytale Day
artists

Artists Day
tulip

Tulip Day
lumpy rug

Lumpy Rug Day
blanket fort

Blanket Fort Day
gum

Gum Day