My Knee Hurts - Old Folks Jokes. My Knee Hurts - Old Folks Jokes. Clean Christian jokes, funny jokes, free jokes, and clean jokes and humor about old people, memory, false teeth, Grandpa and Grandma and more. Enjoy a wide variety of funny Christian jokes, good clean jokes, and family safe jokes and religious humor. An old man limped into the doctor's office and said, "Doctor, my knee hurts so bad, I can hardly walk!" The doctor slowly eyed him from head to toe, paused and then said, "Sir, how old are you?" &