One day a world renowned architect dies and goes to the gates of heaven.
"You may not enter," God tells him. "You have sinned all of your life with no remorse."
So God sends him to hell.
After a few days in hell, the architect approaches satan and says "Oh dark one, I am great builder. If you give me a chance I can make some big changes down here."
Satan agrees to let him work, and after a couple months of renovation hell has air conditioned offices, escalators, water features, and every amenity you could imagine. Satan goes up to heaven and tells God about all of the wonderful things that the architect has done for hell.
After hearing what He missed out on God demands that satan return the man to heaven.
"No way," satan replies "he's mine to keep for all eternity."
God says, "Very well than I'll just have to sue you."
Satan laughs and says, "Where are YOU going to get a lawyer?"