Ready, Aim, Sin!
Moving to a small rural area, a father took his son to school to enroll him. My boy's after larnin', what d'ya have?" he asked the teacher.
"We offer English, trigonometry, spelling, etc.," she replied.
"Well, give him some of that thar trigonometry; he's the worst shot in the family."
Source: Teachers: Jokes, Quotes, & Anecdotes, 2004