Read this account from UFC co-founder Rorion Gracie and weep, fans of privately held companies one has no financial stake in making as much money as humanly possible (via Fighter's Only):
We thought of a moat with alligators. We thought of an arena with sharks around. We seriously thought about an electric fence. But we couldn't in case one guy pushed the other into the moat and he'd get chewed up. We laughed at it, but in Hollywood your mind travels and we just thought of every different possibility... Eventually I settled on the Octagon.