National Dance Day is on July 29th and was created by Nigel Lythgoe, the co-creator of So You Think You Can Dance and co-president of the Dizzy Feet Foundation. It takes place in the United States on the last Saturday
As of 2016, the event continues annually and "encourages Americans to embrace dance as a fun and positive way to maintain good health and combat obesity".
References
National Dance Day Wikipedia(Text) CC BY-SA