When an argument reaches the point of no return, or I'm talking to my sister, I'll pop a yo momma. Heck even my parents and grandparents do it for shits and giggles. However they don't come up naturally in day to day life.
Also, I like the "unjoke" ones, like "yo momma so fat, she risks cardiovascular complications in later life" or "yo momma so fat, she should consider going on a diet in order to lose some of the excess weight".
What can I say. I am a simple person with simple pleasures in life.