I found this one it was funny

Many, many years ago when i was twenty three, I got married to a wido who was pretty as could be. This wido had a grown up daughter who had hair of red. My father fell in love with her and soon the two were wed. This made my dad my son-in-law and changed my very life. My daughter was my mother for she was my fathers wife.

To complicate the matters worse, although it brought me joy. I soon became the father to a bouncing baby boy. My little baby then became brother-in-law to dad. And so became my uncle, though it made me very sad. For if he was my uncle, then that made him brothe to the widow's grown up daughter who, of course was my stepmother.

Fathers wife then had a son, who kept them on the run. And he became my grandson for he was my daughter's son. My wife is now my mothers mother and it makes me blue. Because althouh shes my wife she's my grandma too.

If my my wife is my grandmother then i am her grandchild and everytime i think of it It simply drives me wild. For now i have become the strangest case you ever saw. As the husband of my grandmother, I am my own grandpa!