To explain further, in case some of you haven't been there (or aren't sure that's what I meant):
You can play pinball, or perhaps a sport. Maybe even doing whatever it is you do at work (or at school, for that matter). Same old, same old. Watch the ball drain, watch another baseball flash by your bat (or, for that matter, just hit it nicely...but same old). Whatever.
Then, all of a sudden, under the right circumstances on the right day at the right time...you OWN it. You don't know what it is, you've no idea what is making the difference...but suddenly you're absolutely ONE with whatever it is you're doing.
To continue using pinball as the example, suddenly you're one with the machine. Every touch of the flippers, every move of the ball, is something that you have complete control over. It's not that you're having a good ball (though it usually only lasts for one ball...oh well!), it's that you're actually IN TOUCH with everything, you are ONE WITH THE MACHINE.
I think the most telling thing about such times is that, whereas ordinarily you're waiting for the ball to drain sooner or later...when you're in the "zone," when you eventually lose the ball, THAT'S what comes as a surprise.
At such times you feel like you've transcended your own limitations, and your humanity.
You've had a taste, just a very mild taste, of what we're all capable of, but which we can only hope to grasp on very fleeting occasions.