People really do (kinda) play Quidditch, the flying-broomstick sport of Harry Potter. It was adapted in 2005 by students at Middlebury College and according to the International Quidditch Association (IQA) it is now played by over 300 Universities and High Schools worldwide.
The IQA is hosting a World Quidditch Exposition to coincide with the London Summer Olympics and is offering official Team USA Jerseys. You can show your support of your home country Qudditch Team, use it for cosplay, or just wear it for fun.
Team USA Quidditch Jersey $49.99 ($74.99 for a personalized version) from the International Quidditch Association. Also available for France, UK and Australia.