Pepsi ran a commercial showing a Harrier jet for 7 million Pepsi Points. A business student named John Leonard did the math, raised $700,000, and mailed Pepsi a check demanding the jet.
Pepsi said no. He sued. A judge ruled "no objective person could reasonably have concluded" the offer was real.
Pepsi re-aired the ad with the price changed to 700 million points and a "Just Kidding" disclaimer.