Mike and Pat go out to the bar, and after a few too many drinks, Mike pukes all over his shirt.
"Oh jeez," says Mike. "I told my wife I wouldn't drink too much and now she's going to know I was out boozing it up. She's going to kill me."
"Relax," says Pat. "Just slip a $20 bill into your shirt pocket and tell her some guy puked on you and gave you money for the dry cleaning bill."
Satisfied that this will work, the two have a few more drinks and Mike finally stumbles home.
His wife sees him and immediately goes off on a tirade. "You told me you weren't going to drink too much but you drank enough to get sick and you puked all over yourself."
"No no no," slurs Mike. "A guy puked on my shirt and he gave me $20 to pay for the dry cleaning. See?"
Mike reaches into his breast pocket and pulls out two $20 bills.
"So what's the other $20 for?" his wife asks.
"Oh, that's from the guy who crapped in my pants."