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

Other days

self appreciation

Self Appreciation Day
pumpkin

Pumpkin Day
boyfriend

Boyfriend Day
one

One Day
bounce

Bounce Day
ruby

Ruby Day
cuddle up

Cuddle Up Day
gum

Gum Day
boy friend

Boy Friend Day
chocolate milkshake

Chocolate Milkshake Day