In the haunted house, you can find an unofficial hidden mickey the the cast member do to drive the imagineEARS (disney engineers). In the ballroom scene on the long table, one of the place setting are set up in the shape of mickey ears. One dinner plate for the face and 2 bread plates for the ears. The cast member do this all the time and the "bosses" find it and more them back to the right place. Way, to funny!!!
Also, in Tomorrowland, right above the bathrooms next to TraderMickeys there are 3 techno looking windows. 2 of the three are open and the other, the imagineEARS put a metal barrior over it to close the window. They weren't SUPPOSED to do it, they just did it to be silly.
Also, on Main Street, look at the windows. Every name on every window stands for something in "Walt's life". Look for the window that states M. T. Lott Real Estate. This was the real estate company that bought the land in Florida which was later discovered to actually be Walt Disney. He used the fake name because he already had DisneyLand and knew he wouldn't have gotten such a great price on the land. Say his Real Estate name outloud, it stands for Empty Lot which is what this part of Florida was before he started development out there with many many many acres bought.
Anyway, that's my addition to this post.