Disclaimer: I am in no way affiliated with any party behind the scenes of this event (range/club, sponsor, vendors,etc). I am merely a participant.
When: July 9th, 8am-6pm (check-in opens earlier, the range is live 8-6)
Where: Ahlman's Gun Range in Morristown, MN
Link to Event Website
I expect more information will be provided as the date draws nearer.
I went to OO3 last year, and I really enjoyed the experience. Didn't run into any of the "problem people" you find on gun forums, just guys looking to have some fun enjoying a slightly different 3-gun.
There are no gear restrictions or classes like in true competitions, so bring whatever you train with or enjoy shooting. The only equipment restrictions are on ammunition, which is done to prevent some possible property damages.