1st time - kind of both. We started giving them clues about 3 weeks ahead of time as to the places we would be driving through and had them plot the points on a map (we drove from Chicago to Orlando). Once it was obvious we were heading to Florida, we gave one picture clue a day that revealed the fun things we were going to be doing while we were there: Hilton resort, Gatorland Zip-lining, IFly Indoor Skydiving, Disney Quest/DTD, Magic Kingdom, Cocoa Beach/Space Center, Detroit Tigers Spring Training baseball game). It was SOOOO much fun planning the clues and having them guess each location so they could add another dot/line to the wall map. I still have the map as a souvenier of the trip, and we hadn't even left the house yet!! LOL
They were 6th grade (11 1/2), 2nd (7 1/2), and Kindergarten (just turned 6) for that trip. We went in March of 2012.
The 2nd time was equally as awesome, and maybe even more. It was this past November, so they were 8th, 4th, and 2nd grade (13, 9, and 7). We surprised them the morning we left - our flight time/leaving for the airport time coincided almost perfectly with our normal schoolday routine, so we packed in secret, and woke them up like normal and had them get ready. We arranged for a limo to take us to the airport as part of the surprise, so about 10 minutes before it was due to arrive, we sat them down, said that we have something to tell them, and gave them each a small goody bag. On one side I wrote with Sharpie:
"Who's got it"
"Better than us?"
"NOBODY!!!!"
and on the other side:
"We Are"
"Going to"
"Disneyworld!!!!"
Here were the reactions:
(DS13): "I knew it."
DD9: "Cool!"
DS7: "look! A Crunch Bar!"
DH: "Open your bags!"
Haha....they still didn't get it. I was videotaping, and saw DS13 reading his boarding pass and starting to realize that we were going to be going That Morning, so I told him to share the news with his siblings:
DS13: "Hey guys, we are departing at 9:53am!"
DD9: "You mean we are going today??!!"
DS7: "Where? Where are we going?" (LOL)
THEN they all got it LOL, and all started screaming and yelling and jumped up and hugged DH

telling him thank you (Ummmm, *I* planned this whole thing!!! LOL), then they came over to me and did the same.
I told them that they had 10 minutes before we had to leave, all of their stuff was already packed, and they had 10 minutes to find ONE thing that they could fit into their carryon bag to bring before we left.
DH and I watched for the limo to arrive (we kept the curtains closed), and once it did, we videotaped again as we told them the car was out front already and it was time to go. They opened up the curtains to see the car and there was a huge white limo waiting. They freaked out LOL. We have it on video:
DS7: "A LIMO!!!! You got us a LIMO??!!! How did you guys afford that???!!!"


Totally and perfectly the reaction that every parent hopes to catch on video when doing one of these kinds of surprises!
The entire trip to the airport was so fun and exciting...the kids were so happy, and we had so many stories to tell of near slips, how even their teachers knew about the surprise, how many clues we gave that they totally missed or didn't pick up on, etc. They all agreed that they would LOVE for us to surprise them again!