Last year I took my DS (6) for a suprise trip to Disney. Because I have two younger DS, I had told them that I was going away for a few days to a conference.
The night before we were set to leave he ask me: "mommy one day can we go to Disney?"

YES I said I promise...
We had to leave for the airport at 5:30am, I woke up my son and asked him if he wanted to come and he said yes...
I didn't want to tell him, I wanted him to be completly surprised
So I had to whisper at the airport check in and at the security check that this was a surprise. Tell were all very understanding.
We got to MCO, DS commented on all the mickeys he say wow, still didn't have a clue. Got on the magic express bus, the "movie" started he was happy to see it and was saying I want to go there. He still didn't get it
The woman if front turned and said to him "are you excited?" He said "for what??" "Well to go to Disney?" Just at that time we passed the
Welcome to Walt Disney World Sign. His face was priceless, he in disbelief
That only made it a vacation to remember, he loved that it was all a surprise.
We had so much fun, we went back this pass January with the whole family. Now I'm planning one for next year and it will be a surprise for all 3 kids
