It's a bit long... so how about just the punch line...
Scene: Christmas morning and the two twins go into separate rooms to see what Santa brought to each of them....
The parents went to check on the little optimist and his gifts. They walked into a room with a large pile of Horse Dung piled in the middle. The little optimist was buried up to his waist throwing dung all around. He exclaimed, full of glee......
"You can't fool mee.......I know there's a pony in here somewhere!!!"