Back in the 1960s and '70s, the Road Runners Club of America hosted periodic "postal challenges" in which, rather than coming to a single venue to compete, runners ran at the locations of their choice and mailed in the results for tabulation.

Now, Nike has taken the same idea, moved it from the track to the roads, and updated it to the Information Age.

The even, marketed as the world's first virtual half marathon, will be held in conjunction with the sold-out Nike Women's Marathon and Half Marathon on October 21.  But rather than going to San Francisco to run, participants will simply need to log 13.1 miles on a Nike+ distance-running system, then upload the results to Nike.

It's not a competitive event.  "This is more about running as a social activity," says Brian O'Connor, Nike's global running brand manager.  "It's the unity, which we think is an important part."

Yes, there's a registration fee ($45 until September 15, then $55).  Finishers get T-shirts and Tiffany keychains, and proceeds go to the Leukemia & Lymphoma Society.

Does this spell the end of racing as we know it?  O'Connor doesn't think so.  "You can't replace the experience of a race day," he says.  "This is a way for more people to get involved.  We've not had any negative comments."  Men are also invited to run.

Go to http://nikeplus.nike.com/nikeplus Pace Chart: 6:00 - 6:59 Pace per Kilometer.