Sad news today as we hear of the passing of Dorothy Mengering, better known as David Letterman’s Mom. She died yesterday at the age of 95. Over the years she made many appearances on her son’s late-night shows. She was a great cook, and one of her most popular recurring bits was "Guess Mom's Pies." Here she is on the Thanksgiving episode in 1998. BTW...today is Dave's birthday...he turns 70.