Oops, it doesn't look like 'brown bag lunch day' is a national day..

Other days

fiancee

Fiancee Day
lash

Lash Day
gum

Gum Day
pumpkin

Pumpkin Day
lumpy rug

Lumpy Rug Day
reading

Reading Day
cat girl

Cat Girl Day
nail polish

Nail Polish Day
hannah

Hannah Day
stud

Stud Day