I thought this one was pretty good 
Three elderly golfers are walking down the fairway.
"Sixty is the worst age to be," said the 60-year-old, "You always feel like you have to pee. And most of the time nothing happens."
"Ah, that's nothing," said the 70-year-old. "When you're 70, you don't have a bowel movement anymore. You take laxatives, eat bran, you sit on the toilet all day and nothing happens."
"Actually," said the 80-year-old, "Eighty is the worst age of all."
"Do you have trouble peeing too ?" asked the 60-year-old.
"No, I pee every morning at 6.00 am. I pee like a racehorse; no problem at all."
"Do you have trouble having a bowel movement ?"
"No, I have one every morning at 6.30 am."
Puzzled with this the 60-year-old said, "Let's get this straight. You pee every morning at 6.00 am and poop every morning at 6.30 am. So what's so tough about being 80 ?"
"I don't wake up until seven."