The inaugural running of the Star Wars Half Marathon – The Dark Side, will cap off a weekend of running activities at the resort which will include a 10k, 5k and kids races.
All of the races begin at Epcot with the half marathon and 10k ending in ESPN Wide World of Sports. They also begin pretty early (5 and 6am!), presumably to avoid runners having to dodge regular park visitors.
There are about a million themed races out there these days, but this one definitely sounds cool. More info about the various races, including registration info, can be found here.