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

Other days

ruby

Ruby Day
gum

Gum Day
gallery

Gallery Day
hiv awareness

Hiv Awareness Day
stud

Stud Day
azonto is acceptable

Azonto Is Acceptable Day
ride the wind

Ride The Wind Day
self appreciation

Self Appreciation Day
stress awareness

Stress Awareness Day
offer

Offer Day