Kite Gen Research out of Italy loves to fly kites... They currently have a prototype 200 square foot kite that goes up to 2,600 feet (where the air currents are 4 times more powerful) As the kite goes up, it spins a generator that produces 40,000 watts of power.
When the kite reaches the it's altitude it unspools and motors quickly bring it back down - then it starts the process again and again and again...
They are now working on a 1500 square foot kite (and generator system) which should be ready by 2011 that will generate 3,000,000 watts of power - enough to power 9,000 homes...