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

Other days

ruby

Ruby Day
lumpy rug

Lumpy Rug Day
my little pony

My Little Pony Day
bow tie

Bow Tie Day
gallery

Gallery Day
lost sock memorial

Lost Sock Memorial Day
lash

Lash Day
youth

Youth Day
tulip

Tulip Day
reading

Reading Day