Two neighbours get together.  
“Guess what — I killed my mother-in-law,” says one.  
“Liar!” says the other.  
“Come along, I’ll show you.”  
So he takes his neighbour to his garden. Right on the front of the house there is a fresh grave, from which a naked butt peeps out.  
“Why did you leave the bottom out?” the neighbour wonders.  
“Well, I figured i’ts an easy way to park my bike.”