It is the idea that Jordan Wild and Sandy Metwally receive an increase in sexiness of exactly 15% every day. This will eventually reach the point where the accumulation of all the percentages make a number which is impossible to determine.
This is increased by 90% on the day that either Jordan's coat or Sandy's shoes are worn by the invididual. They cannot both be worn on the same day, however, as the total percentage would reach over 100% and cause the appocalypse.
Person 2 : It's Jordan and Sandy, haven't you heard of the Wild-Wally Theory
Person 3: A OWL