I was just visiting The Yarn Harlot's blog post about procrastinating. People commented to sympathize and encourage, and at least two people suggested she start the laundry and then go for a bike ride.
PLEASE do not ever start your washer, dryer, dishwasher, or other appliance and then leave the house. One day I just ran across the street for five minutes to deliver dinner to a neighbor, and came home to a house full of smoke. Our dryer malfunctioned, and if I'd been another five minutes the dryer would have been in flames.
I know people who haven't been as fortunate, and lost their homes (at least temporarily) to a fire started by an untended appliance. Yes, it is tempting to just let the laundry do itself while you run some errands, but I promise you it is not a good idea.