The da Vinci Prize
An imaginary annual prize in 1442 for the highest human powered flight. The technology required for human flight isn't extant so competitors jump with springs. 25 years later there's no human powered flight but spring technology is highly optimised.
The Shieber Argument
"Imagine that a prize for human-powered flight were set up when the basic science of the time was far too impoverished for such an enterprise, say, in Da-Vinci's era. The da Vinci prize, we shall imagine, is constituted in 1492 and is to be awarded to the highest human powered flight. Like the Loebner Prize, a competition is held every year and a prize must be awarded each time it is held. The first da Vinci competition is won by a clever fellow with big springs on his shoes. Since the next competition is only one year away (no time to invent the airfoil), the optimal strategy is universally observed by potential contestants to involve building a bigger a bigger pair of springs. Twenty-five years later, the head of the prize committee announces that little progress has been made in human-powered flight since the first round of the prize, since everyone is still manufacturing springs" (Shieber, 1994, p. 76).
Source: Shieber, Stuart (1994). "Lessons from a Restricted Turing Test." Communications of the ACM, 37:6.