Zac Brown Goes Midget Bowling

It all went down at the the Sturgis Motorcycle Rally in South Dakota ... where Zac was enjoying the "Midget Bowling" tournament at the M F'N Bowling tent.

For the record, events involving the tossing or throwing of little people is generally frowned upon by the little person community ... but event organizers insist "Midget Bowling" is perfectly legit.

In fact, TMZ spoke with "Short Sleeve Sam" -- the self-described "midget" at the center of the action -- who tells us he was a ready and willing participant in the activity ... and insists Zac didn't do ANYTHING wrong.

Sam claims "midget bowling" is safer than "midget tossing" because the little people are never airborne ... "it's just a modified slip and slide."