My dad beat up Cassius Clay!
Nobody expected it, least of all me! But we were at the international food products expo, I couldn't have been older than seven or eight at the time, and cassius clay, AKA Mohammed Ali was giving a presentation on the virtues of a device that sealed food in small vaccum locked bags. 
My dad worked for Allied Alluminium at the time, which was already hurting from the plastic wrap craze, and he wasn't having any of it. He voiciferously heckled cassius clay as the ex-heavyweight boxing champ of the world attempted to give his presentation, calling him names like "you dirty bag wrapping jew nigger" and "you fucking spook cling-wrap cock-sealer". 
Cassius ignored my dad as long as he could, but when my dad started to talk about how "Mohammed" was going to vaccum-seal a holy koran in plastic so he could stuff it into his mother's vagina, it was on! Cassius clay bellowed loudly and surged through the crowd like the people were just cardboard cut-outs.
My dad didn't budge an inch though, he just stood there and let Cassius Clay punch him right in the face! It was a massive left hook, and everyone thought my dad would be KO'ed right there on the spot, but he held his ground! Cassius Clay unleashed a flurry of jabs to my dad's face and midsection, pummeling him like an empty sack, but never knocking him down!
After a spectacular right cross, everyone in the crowd seemed to notice at once that not only was my dad not hurt at all, he had a raging hardon! I was so embarassed! My dad started urging Clay to hit him harder, calling him a "pussy" and a "faggot". This enraged Cassius, and he beat my dad even more furiously, but he just could not knock my dad out!
Finally, Cassius Clay missed a step going in for a hard right to my dad's midsection and slipped onto the ground. My dad made his move. He clamped the 6'3 Kentucky powerhouse in a headlock, and held him to the ground in a painful submission hold. "I'll show you the real sweet science!" my dad shouted, and then in front of the whole food products convention, tore off Cassius Clay's pants, exposing his tiny hairless penis, like that of a child. 
My dad whipped out the huge erection that had obviously been growing the whole fight, exposing a good eleven inches of hairy cock to the shocked onlookers. Never letting go of Clay for a second, he pulled Clay's boxer shorts off with his foot, as Clay squealed and tried to buck him off like a horse. But there was no shaking my dad. He shouted "I am the greatest!" and proceeded to fuck Mohammed Ali in the ass. 
In two secconds he had crammed his entire cock up Ali's ass, and was riding him like a bucking bronco. Several men tried to come to Clay's assistance, but Clay was so insane with fright that he knocked several of them away, severely injuring at least one. My dad continued to pump his cock into Clay's ass, punching Clay in the back of the head with each thrust, further disorienting him. 
Finally, my dad came in Mohammed Ali's ass, with a wild "yahoo" just like a cowboy. Ali slumped to the ground weeping and defeated, and I could see tears of joy in my dad's eyes as the security guards hauled him away. Mohammed Ali may have been the heavyweight champion of the world, but in my eyes, and those of everyone who saw him at that convention, he'll never measure up to the true champ; My Dad.