1. There's a smaller basketball court hidden underneath the basketball court in the Matterhorn
  2. The Haunted Mansion is actually haunted, because ghosts are real
  3. The Indiana Jones ride is in a real temple, but a Jewish one
  4. Nobody has actually ever been on the Monorail
  5. If you hug any costumed characters from behind they have to go to prom with you
  6. All of the food is vegetarian unless it's Mickey shaped
  7. There's a hidden tiki bar underneath the Dole pineapple stand in the courtyard. Recite the names of each Hawaiian god (and what they're gods of) from memory to gain admittance.
    Suggested by @saytrumbo
  8. If you yell "Andy is coming!" Within earshot of any Toy Story characters they drop to the ground
    Suggested by @Celina
  9. There's an underground area for characters to fart. No one likes a smelly princess.
    Suggested by @ChristaBullock