We were at the after party for the Food & Wine Marathon in Epcot a few months ago. It was open until 3 am and let me tell you--it was AWESOME! People, including us, did not want to leave at 3. We could have stayed til 5 or later! Seriously.
It was so fun, so mellow, so UNpacked. No kids--a real plus! That really changed the situation. Don't get me wrong--not a kid hater, have kids, love kids. But kids at Disney at 3am is not a great idea. It was a completely different and wonderful experience.
Characters were out in pairs and really posing for fantastic, not your typical pictures. Example is Pinnochio and Geppeto, we all posed like puppets hanging on strings. Pinnochio was running up and down the stairs, very playful and full of mischief. Princesses were dancing with "other" princes and posing for photos with other princesses.
It was one of the best Disney experiences we've ever had.