http://www.zeromotorcycles.com/electricross/
This seems to be a 24 hour endurance event. The schedule is from 10 AM April 4 to 10 AM April 5. They say they'll be providing battery packs & recharging to entrants (?? who have compatible bikes ??).
It's being held at an offroad motorcycle track in San Jose. I'm looking into attending and doing some reporting from the event.
Apparently there's still time to enter.