April Fools
Little Jeremy was blind (aw!). One evening, his mummy put him on her knee and said, "Jeremy, I have a very special surprise for you. Tonight, if you pray very hard, when you wake up, you'll be able to see."
In great excitement, Jeremy stumbled upstairs, threw himself down next to his bed, and prayed his little heart out. "Please God, please, please, please give me sight. I'll be a good boy all the time, and I'll never use my eyes to look at naughty things or anything." (etc.) The next morning, his mother is awakened by howls from Jeremy's room.
She rushes into him. "What's wrong, son?"
"I still can't see!" he wails.
"Ha ha!" laughs his mum. "April fools!"