Here's another joke:
A mother is writing a letter to her son who is in prison: "Ever since they've sent you to prison the house has been in disrepair, the garden hasnt been dug up or fertilized, the potatoes havent been planted, I dont know what to do!"
The son replies to her: "Dear mother! Do NOT dig in the garden! I've burried something there that will get you in prison and that will get me a few more years tacked on!"
A while later the mother replies: "After receiving your last letter, a few policemen came in and were looking for something in the garden, dug everything up, didnt find anything. They cursed a lot then left."
The son replies: "Dear mother! I helped you the best I could! Plant the potatoes yourself!"