Then there's the one about the proctologist who decides to become an auto mechanic. He quits his practice and takes a course in engine rebuilding. For the course final, he has to take an eight-cylinder engine completely apart and put it back together again. The instructor says there are 100 points possible for the test.

When the grades are posted, the proctologist gets a 120.

"I thought there were only 100 points possible," he says to the instructor.

"That's right," the instructor replies. "But I gave you 20 bonus points for doing all the work through the tailpipe!"