Did you know there were sort of secret days on which visitors dress up to go to the Magic Kingdom? Some really epitomize the term "dress up," as in "Sunday morning church and stroll clothes." The most exquisite dress up day would be Dapper Day and it occurs twice a year.
Dapper Day has its own website, which is where the above montage came from. The next Dapper Day in Orange County is September 18--upwards of 20,000 people come dressed in their finest from their era of choice, and you can join them!
I called the dress up days "sort of secret" because there's a website or facebook page for many of them. You just have to know where to look for it. Here is a list of the days that was published by LA Weekly (thank you, thank you!).
The day coming up next on the calendar is April 26: Pin-up Day. This involves goodie bags and special group pictures at certain rides. See the linked FB page for times. Also see their links for what constitutes a pin up outfit. They're much milder than I thought. Attitude seems to be the defining factor of the ensemble.
For the record, I think that Disneyland does not allow full-on costumes. Star Wars fans can wear tee shirts, etc. but not their Padawan or Jedi Master outfits. On Dapper Day--well, when does a suit with a bow tie become a costume? It doesn't! Get thee to a habadashery!
Gay Days are old hat by now--but Boomers like me remember when, back in the 70s or 80s, this was a big issue. Hah! According to many, any day is gay day at the Magic Kingdom. For the record, however, Gay Days fall in October.
Other special days include the twice-a-year Raver Days, Dr. Who day--also called Galliday--and the Harry Potter Day. Then there's Lolita day, Tikis, steampunk, rockabily, Bats, and goths. And lions and tigers and bears--well, why don't they have an Oz day?