Admittedly, these are rare. Most T-shirt slogans, no matter how witty they try to be, usually wind up falling flat.
However, I recently saw one that made me laugh out loud.
It was a plain, black shirt with 'great smokey mountains' in a small type face on the front. The back was something very different. In large, white letters the shirt read, 'PADDLE FASTER! I hear banjo music'.
Have you seen any really good T-shirts lately?