Mine was when i was younger and getting to the age where i didnt believe in santa any more, i had a big double walk in wardrobe in my bedroom, and my mum and dad put all our presents in there, i have an elder brother and sister, and we all knew that it was my mum and dad who actually put the presents under the tree, so this year, after putting the presents in there, we went to have dinner, over dinner we all decided we were going to booby trap the door in someway, so the 3 of us went up after dinner, and all did a different knot or trap on the door somehow so we would know if it had been opened. In the morning we went downstairs, we had a big open fire place and there were big foot prints of soot out and all the presents under the tree, we raced up stairs but the door and the booby traps were intacked!!!
It wasn't until a few weeks ago i finally discovered the real truth, over dinner they had moved all the presents before we had time to booby trap the door, and us 3 kids didnt even think to look in the wardrobe as we had already put all presents and seen them in there!!!