Love the Indy pole. My son races through that room because he doesn't want to hear the loud noises.
Also in Indy, in the room right before they show you the safety video, there is a box with a big rope. The sign says don't pull on rope, but of course you can pull it. You hear workers with British accents telling you to stop, there are workers down here, etc. After about 3 pulls, you hear them fall.
When leaving Indy, once you almost reach the entrance, on the right there is a phone booth. If you pick up the phone you'll hear international conversations.
On Winnie the Pooh, I always pay homage to the Country Bear Jamboree. After the dream sequence, you pass through a doorway, but for the life of me I can't remember what room you enter. Anyway, if you turn around and look up, you will see Melvin the Moose and 2 others, but again I can't remember who right now.
I could go on, but I'll let others chime in.