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

Other days

cuddle up

Cuddle Up Day
brow

Brow Day
reading

Reading Day
boba

Boba Day
comfy

Comfy Day
ponytail

Ponytail Day
nae nae

Nae Nae Day
lost sock memorial

Lost Sock Memorial Day
kiss a ginger

Kiss A Ginger Day
ruby

Ruby Day