Happy New Year: "Death by Degrees" bike ride

From the board of directors of Bike/Walk Tennessee we would like to wish everyone a happy new year as we ring in 2012. There is a ride organized by Knoxville locals Gary and Helen Picou on New Years's Day named the "Death by Degrees" ride. As its name suggests, the ride is one that goes for the number of miles in degrees that are present at the start. So, if say it is a warm 60 degrees at the start, then the ride is a 60 miles ride. On the other hand, if it's an utterly frigid 0 degrees, then the ride is cancelled. A tamer option exists for riding the number of kilometers in derees Celsius. Setting ride distances based on temperature is quite creative. Are there other creative rides out there with an element of chance?