|Rose hips. Nikon D7000
I remember as a child that there was a 'joke' stall sometimes at the local market; a deep crowd of like-minded kids were always crowded around it and the stall's daily take must have been huge.
The usual 'fly in the ice cube' was fun, and the 'Whoopee Cushion' caused great mirth until it was sat on far too hard and burst.
But the more subtle jokes, such as lacing one's sisters clothes with itching powder, were sometimes more satisfying :)
The only issue was that a decent supply of itching powder was needed to ensure that at least one item of clothing was worn (in particular on April Fool's day, but action on any other day was also welcome). I am not sure which adult let slip the secret, but a rose hip this size would certainly have made me smile with the thought of how many thousands of tiny scratchy hairs it had inside; just waiting to be fluffed up and released onto an unwilling victim!