Yo mama's so fat that the National Weather Service names all of her farts.
Yo mama's so fat that when she ran out into the street and I tried swerving around her, I ran out of gas!
Yo mama's so old she has an autographed Bible.
Yo mama's so stupid she sold her car for gas money.
Yo mama's so ugly, we call Henry Ford our savior for inventing a way to escape her.
Yo mama's so fat that when God said "Let there be light", he told her to get the fuck out of the way!
Yo mama's so stupid that she yelled into an envelope to send a voicemail.
Yo mama's so ugly, when she looked out the window, she got arrested for mooning!
Yo mama's so fat, when she walks past the TV, you miss 3 episodes of the show!

a joke to tell when you're in a really trite mood and feel like laughing for no exact reason.