Zen for me is best achieved mountain biking or tree climbing. Focus comes when a moments inattention will result in pain and often damage.
Real Zen comes when I hit a tree at speed or come off the bike and head meets ground with force...it's in those moments laying on the ground with stars swirling above, before the pain sets in and before the self check for the severity of damage. All is good even then if no bones are sticking out and the bleeding is easily stoppable.
Similar to tough-love, this must be tough-Zen !