One year my parents got us a trampoline. It was set up and then the blinds were closed. They made sure we didn't go outside by feeding the dog before I could and taking out the trash before my brother could. We didn't think much of it until my parents sent us up to the neighbor's with a plate of cookies. Oops. There, in our backyard, was the shiny, new trampoline. We were giddy with excitement but we didn't let on that we'd seen it.
The next day we opened all our gifts and then my parents sent us outside. We pretended not to see it and walked back in. Eventually we "saw" it and clued my parents in on their neighborly blunder. We loved that trampoline to death and then we gave it to our cousins who, I think, are still loving it.