We went last October, but had it booked since August. We didn't tell our DS4 that he was going. Although we had a few "slip ups" where we said something accidently

. But luckily DS didn't hear it or catch on (phew).
DH was going to be down there for a business conference so DS came with us to drop daddy off at the airport. We also told him that he would come with me to pick daddy up from the airport. So he knew he was going to go inside the airport. The last day of DH's business trip was the day DS and I were going down to meet up with him for our first real family vacation.
At 4:30/5 am on 10/25/06 I get the video camera all set up to get his reaction to being told he was going to Disney World. And wouldn't you know it, the stupid camera wasn't giving me a picture

. I went into my room to try and fix it and about a minute later, DS knocks on my door. I open it and there he is, rubbing his eyes, groggy and upset that I woke him up (can't blame him there). I then tell him that he isn't going to the airport to pick up daddy today, that we're going to Disney World to meet up with him. Didn't phase him at all. All he wanted to do was go back to sleep, and who can blame him.
I get him ready to go. He didn't know it, but I also had a Disney Enchanted Call from Mickey scheduled for 7 am. By that time, the camera was working (yeah!) and was all set to record. The call comes in and I immediately put it on speaker phone give it to DS4 while I'm recording him. He's there listening so intently as to was was being said by Mickey. Then I see this big smile about a mile wide forming on DS when Mickey says "I'll see you real soon." I believe that's when the realization hit him that he was going that day to see Mickey Mouse, because right after the call was done, he looks up at me and asks, "Can we do that again?" Then proceeds to start jumping up and down asking. He was so excited at that point. It was priceless and daddy got to see the video with DS's reaction once we got settled into Pop.
One thing I have to mention here. Everytime DS saw a Disney commercial or went to the web site he kept asking to go. Before actually booking our vacation we were talking about it going and DS got his hopes up. After we had actually booked it and DS asked about going, I felt like a mean mommy telling him we couldn't afford to go. I could see the disappointment and the tears forming when I would tell him we couldn't. But seeing his face when he realized that he was going on that day made up for it.