We just surprised our son this week, as he turned 5 on April 9.
For his last present, we gave him two presents to open. The first was a package of the free custom maps that you can order from Disney. Inside was a little paper I had done up on the computer as a certificate with pictures that showed we were going to Disney, staying at Poly with the volcano pool and flying down. The second present was the Birnbaum WDW for kids book.
Now, I don't know if it's because I've been talking about Disney and things to do "whenever we go back, whenever that may be," lately. Or maybe b/c he's really into SpongeBob and that's not at Disney. I don't know. He just wasn't that excited about it at the time. I will admit I was disappointed b/c I've been planning this since January. A few days have now passed, and he's getting more excited about it. We spent about a half hour tonight online picking out stuff that we want to do. Unfortunately, he wants to do Toy Story Mania, and it's only open to AP when we are there. Oh well!
I must also add that this is not his first trip to WDW, so I don't know if that has any bearing on his reaction.
So, please surprise your child. Please have fun with it! But please don't be upset if you don't get the reaction you want at first. It will come!