Bun Twitch

An obese woman goes to a doctor to be put on a drastic weight-loss program. The doctor tells her that she can eat anything she likes but that any food must be inserted up the anus. The woman agrees and four weeks later comes back for a check-up. The doctor is very pleased with the woman’s progress but is concerned that the woman’s hips keep twitching constantly. 
“When did that hip twitching start?” asks the doctor. “That's not twitching,” replies the woman. “I’m chewing gum.”

Large Violas

Q: Why are violas so large?
A: It is an optical illusion. It's not that the violas are large, just that the viola player's heads are so small.