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

Other days

frozen yogurt

Frozen Yogurt Day
stress awareness

Stress Awareness Day
one

One Day
tulip

Tulip Day
promposal

Promposal Day
youth

Youth Day
ride the wind

Ride The Wind Day
gum

Gum Day
blanket fort

Blanket Fort Day
unicorn

Unicorn Day