Yo.

Your moms is so old, she sat behind Jesus in the 3rd grade.

Your moms is so old, when God said, "Let there be light", she flipped the switch.

Your moms is so fat, she sat on a quarter and squeezed a booger out of George Washington's nose.

Your moms is so thin she dodges rain drops.

Your moms is so thin, she hides behind STOP signs.

Your moms is so stupid, she got lipstick on her steering wheel by for trying to blow the horn.

yo mammas so ugly that when she was born madusa turned in her grave

Your momma's so fat that when she got in the elevator the only way she could go was down.
Your momma's so fat that when she jumped for joy, she got stuck (go Russell Peters!)

Yo mama so stupid she thinks Montel Williams is a Jamaican gossiper.

your momma's so old, when she was young, rainbows were black an white
your momma's so old and fat that when God said "Let there be light" he told her to move her fat ass out of the way
your momma's so old, when she was born, the Dead Sea was just getting sick
your momma's so old, she's got hieroglyphics on her drivers licence
your momma's so old, she walked into an antique store and they kept her
your momma's so old, Jurassic Park brought back memories
your momma's so old, her memory is in black and white
your momma's so old, her birth certificate expired
your momma's so old, when she was in school there was no history class
your momma's so old, she co wrote the ten commandments
your momma's so old, the candles cost more than the birthday cake

your momma's so hairy, she has afros on her nipples
your momma's so hairy, you almost died of rug burn at birth

your momma's so ugly, just after she was born, her mother said "what a treasure" and her father said "yes, let's go bury it"
your momma's so ugly, her mom had to be drunk to breast feed her
your momma's so ugly, she turned Medusa to stone
your momma's so ugly, they pay her to put her clothes on in strip joints
your momma's so ugly, people go as her for Halloween
your momma's so ugly, your father takes her to work with him so he doesnt have to kiss her goodbye

your momma's so stupid,she sold the house to pay the mortgage
your momma's so stupid, she thought Sherlock Holmes was a housing project
your momma's so stupid when she saw a wrong way sign in her rearview mirror she turned around
your momma's so stupid, when she saw the "NC-17" sign, she went home and got 16 friends
your momma's so stupid, when your dad said it was chilly outside, she ran out with a spoon
your momma's so stupid, she used a vibrator for an egg beater

your momma's so nasty, she puts ice down her drawers to keep the crabs fresh
your momma's so nasty, she has a sign by her pussy saying "warning: may cause irritation, drowsiness and a rash"
your momma's so nasty, she went swimming and made the Dead Sea

your momma's so fat, when she was diagnosed with with the flesh eating disease, the doctor gave her 15 years to live
your momma's so fat, her cereal bowl came with a lifeguard
your momma's so fat, when she steps on the scales it says 'one at a time please'
your momma's so fat, when she went to the beach, Greenpeace tried to drag her back in the water
your momma's so fat, when she sat on a rainbow, Skittles fell out
your momma's so fat, she makes Big Bird look like a rubber duck
your momma's so fat, when she dances she makes the band skip
your momma's so fat, they had to change "one size fits all" to "one size fits most"
your momma's so fat, when she goes in the sea at the beach, she changes the tide

your momma's like a goalie; she changes her pads 3 periods
your momma's like a dollar bill; she gets handled all over the country
your momma's like an ice cream cone; everyone gets a lick
your momma's like the Panama Canal; vessels full of seamen pass through her every day
your momma's like a squirrel; she's always got some nuts in her mouth
your momma's like Humpty Dumpty; first she's humped, then she's dumped
your momma's like the Bermuda Triangle; they both swallow a lot of seamen
your momma's like a street lamp; you can find her turned on at night on any street corner
your momma's like a turtle; once she's on her back she's fucked
your momma's like a paper towel; picks up any kind of slimy wet stuff
your momma's like a bowling ball; round, heavy, and you can fit 3 fingers in
your momma's like a bus; guys climb on and off her all day
your momma's like a christmas tree; everyone hangs balls on her

thank you enigma for coming up with alot of new material (mostly)
I have one to add to the last few.
your mammas like a light switch, a 4 year old can tern her on.

Yo momma is so fat she sat on a dollar and made four quarters.
Yo momma is so fat the only pictures of her are satelitte pcitures.
Yo momma is fat she was laying in the ocean and Spain claimed her for their new world.
Yo momma is so fat she goes to a resturant, looks on the menu and says,"OK".
Yo momma is so fat she has more chins then a Hong Kong phone book.
Yo momma is so fat the Japanese military attacked her because they thought she was Godzilla's wife.

Whoa, what the hell is going on here.