Last year Linus and I were in Walgreens. They had their Halloween display out, and it included Winnie the Pooh and Tigger inflatables dressed in Halloween costumes. Linus (then 3!) totally out-witted me. Here's our conversation as we walked in:
L: Mommy, who is that?
M (slightly confused because I knew she knew who it was): Pooh
L: And who is that?
M (more confused because I really knew she knew who it was): Tigger
L: Oh. Do you know what Tigger says to Pooh at Halloween?
M: No, what?
L: TIGGER TREAT! (Get it? Tigger treat---> Trick-or-Treat)
The people who were near us cracked up, which just fueled Linus on. The WHOLE time we were at the store, and for days afterward, all we heard was "Tigger Treat!"
One of my friends loved it so much that she loaned us a Tigger costume. Poor Linus, she put it on, but it freaked her out.
Then I offered a bribe to get her to smile. It worked!
Then she got to change. She decided to be a ballerina. We took her trick-or-treating. Unfortunately, she didn't get the concept of staying at the door after she rang the doorbell. Oops!
I'll let you know how this year goes. :)