250 Free American Airlines Miles
I timed it and it took me just 90 seconds to get 250 free miles by signing up for a Best Western guest account and setting it to credit to AAdvantage. It would have taken me 60 seconds if I realized that you had to enter your American frequent flyer number in all caps. After you register, you can also earn a bunch of AA points for stays at Best Westerns, though nothing as good as last year's hearty Hyatt airline bonuses which basically earned me a one way first class ticket from EZE to JFK (even though I wasn't that impressed with AA's First Class product, it was still a great promotion).
At the rate it took me, it would only take me 10 hours to accrue a business class ticket to Tokyo!
Tip of the hat to Miles Quest for this one.