We can't blame this guy for wanting to get his lawnmowing overwith as quickly as possible. But 100mph? He could lay waste to a football field in 2 minutes, 42 seconds. You're looking at the work of Project Runningblade, a British group that modified this Countax lawnmower that will attempt to mow down the world record.
Strangely enough, to break a world record for lawnmower speed, you don't actually have to be cutting any grass at those dizzying speeds. The Guinness Book of World Records only requires that the speedy lawnmower must have mown some grass on the same day it goes for the record speed, and be built of lawnmower components by a recognized lawnmower manufacturer.
Project Runningblade must beat the current world record of 80.792 mph, set at the Bonneville Salt Flats. There's grass at the Bonneville Salt Flats? Who knew?