I have another one- its a tad crude, so all you young 'uns out there, cover your screen or something
Anyway, here goes:
An old farmer living with his son steps out to the backyard and sees the grass has grown considerably.
He turns to his son and says to him "Son, could you please mow the lawn? I'm a tired old man, I have arthritis and I can't do it anymore"
The son obliges and takes the lawnmower.
Some time later the old man comes out to join his son in the backyard. He says to him "you did a fine job, Son. But you left those two patches over there untouched. Why is that?"
"See that patch?" says the son, pointing to one of the patches "That is where I had my first ever sexual experience."
The old man is susrprised and says "really? Then what about that other patch?"
"Oh, thats where her mother stood watching us"
The old man is totally shocked "you mean to tell me you were doing her while her mother watched you?!"
"And what did the mother say?"
To which the son replied: "Baaaaaaaa......"