Oops, it doesn't look like 'pretend to be a time traveller day' is a national day..

Other days

martini

Martini Day
nae nae

Nae Nae Day
fiancee

Fiancee Day
gum

Gum Day
embarrass your best friend

Embarrass Your Best Friend Day
tell a fairytale

Tell A Fairytale Day
african immigrant and refugee hiv and hep awareness

African Immigrant And Refugee Hiv And Hep Awareness Day
boy friend

Boy Friend Day
artists

Artists Day
boyfriend

Boyfriend Day