The Thurn und Taxis family of Germany created Europe's first mail service back in the 16th century and has scads of profitable business ventures to this day. When Prince Albert von Thurn und Taxis turned 18 in 2001, he inherited a fortune. According to a 2007 report by Forbes magazine, he's worth a cool $2 billion, making him the world's youngest billionaire.
Want to check out more lists? See All Lists.
Helen Davies, Marjorie Dorfman, Mary Fons, Deborah Hawkins, Martin Hintz, Linnea Lundgren, David Priess, Julia Clark Robinson, Paul Seaburn, Heidi Stevens, and Steve Theunissen
HowStuffWorks looks at companies that have successfully switched from five days of work to four, with spectacular results. So, why don't more try it?