Some fo my favorites are....
"your mom is so poor, when she finds a thrown cigarete butt she says thank the lord we have heat"
"your mom is so poor, when I asked her why she was kicking a tin can down the street she said she was moving"
"your mom is so fat, you can use her underwear for bungee jumping"
"your mom is so ugly, she has to cover herself with mud so homeless people well accept her money"
I good resource to your mom jokes can be found at...