Depending which way you want to look at it, a new entrant to the car hire industry, or a substitute for buying a car, has just been announced by Sir Stelios Haji-Iaonnou and Brent Hoberman (co-founder of lastminute.com).
Their new service, called Zipcar, will rent cars by the hour and will be test launched in spring 2012.
http://www.ft.com/cms/s/0/68d4cba2-249d-11e1-bfb3-00144feabdc0.html