On one of our first trips to WDW we weren't familiar with U.S holidays and without realising it booked a character dinner at Crystal Palace on Memorial day. We first realised something was wrong when we arrived at the car park at the TTC and was told it was full and we were re-directed to the Epcot parking lot and told to get the Monorail back to Mk! I don't remember if we actually got on any rides that evening, but I do remember when we came to leave the park that Main Steet was so grid-locked that they opened up a castmember exit at the top of Main street and we left the park through that gate.
Yes it was busy, but these are still precious memories!
I know this story makes me look like a total idiot, but hey, if you can't laugh at your own mistakes....