Computational complexity theory tries to find equivalence classes of problems that can map to one another. Each class has a primary representative such as TSP (travelling salesman problem) or 3-SAT that memorably capture the essence of the class. While it's not clear that you can map Grand Theft Auto to anything useful, you might be onto something here: Imagine a mechanical turk system where the grunt tasks are remapped onto inherently enjoyable gameplay scenarios. It would be an arbitrage play between turk vendors needing menial tasks done, and players needing entertainment. Recaptcha is a (brilliant) example, but I don't know of others. Maybe UAV control might be one. (Note that mapping one valuable task to another enjoyable task is a different idea than the "gamification" fad of inventing events to adorn with tawdry badges.)