Around 2002, some eye doctors began to get fiery letters from an ophthalmologist in Bowling Green, Ky. He was trying to recruit them to do something odd: sign up to be "board-certified" by a medical board that hadn't existed a few years before.

The Kentucky doctor was Rand Paul -- the son of libertarian icon Ron Paul, who hadn't yet run for office himself. Paul managed to persuade around 50 or 60 doctors to pay the $500 and be certified by his new board. But he never managed to win recognition from the medical establishment, and the board had nearly faded away by the time Paul ran for office himself in 2010.

Letters to DocsRand Paul's recruiting letters for his opthamology board