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

Other days

gum

Gum Day
bounce

Bounce Day
nail polish

Nail Polish Day
self appreciation

Self Appreciation Day
hot chocolate

Hot Chocolate Day
eat what you want

Eat What You Want Day
pick me

Pick Me Day
youth

Youth Day
brow

Brow Day
lumpy rug

Lumpy Rug Day