Nothing funnier than a good "Yo mama" joke. Here are some of my faves:
Yo mama is so poor, she watches tv with one eye to save energy
Yo mama is so poor, her dog gives her its leftovers
Yo mama is so poor, the rainbows in her neighbourhood are black and white
Yo mama is so stupid, she though mood swings was a mew ride at Disneyland
Yo mama is so stupid, she thought Chris Rock was a new type of crack
Yo mama is so stupid, she got locked in a mattress store and slept on the floor
Yo mama is so old, she owes Moses a Rand
Yo mama is so old, her first christmas was THE first christmas
Yo mama is so old, her high year book was printed on a rock
Yo mama is so ugly, she went to the zoo and the animals pointed at her
Yo mama is so ugly, your grandma threw her on the street and got charged with littering
Yo mama is so ugly, her birth certificate is an apology letter from the condom factory
Yo mama is so greasy, her freckles slipped of her face