What is the half-life of a really bad joke?

(Please note that the absurdly easily offended should avert their eyes, or something.)

Two guys are in the men's room finishing up their business. One guy finishes and heads for the sinks to wash up; the second guy finishes and heads for the door. The first guy says--quite sanctimoniously--to the second "At Texas A&M, they teach us to wash our hands after we use the restroom." The second guy turns around, rolls his eyes and responds "At the University of Texas, they teach us not to pee on our hands."

See? That's perfectly good brain space that I might have used to remember some calculus, or at least another teevee theme song.

before - after