Boxing : Ancient boxing didn't have many rules, nor did it have rounds. Two fighters would keep going at it until the other was knocked out or admitted defeat. There were no weight classes (fighters were chosen randomly), and there was no rule about hitting your opponent when he was down.
The Equestrian Events: consisted of Chariot Racing and Racing. In Chariot Racing, there were carts pulled by 2 horses, and another pulled by 4. Each racer had to do 12 laps around the stadium track (about 9 miles). Horse racing had separate classes for full-grown and foals.
Pankration: Was a form of a combination of boxing and wrestling. The two entrants wore no hand wrapping. The only rules were that no biting, or the gouging of the opponents eyes were prohibited. Other attacks, like kicking in the stomach, were perfectly legal. Like boxing and wrestling, there were separate classes for boys and men.
The javelin throw was an event where a man-high length of wood with a sharpened end was thrown and it's distance measured. During the jump event (also called the Long Jump), a man held lead or stone weights, which they would swing behind their backs to propel themselves further.
Running: During ancient times, there were 4 types of running events; these events were also called the stadion, the oldest events in the games. Each type of running event was longer than the last; there being a 1-stade (the length of the stadium, about 192 meters), and up to a 4-stade. And long-distance races could have been as long as 7-24 stades.
Wrestling: To win a wrestling match, one contestant had to throw his opponent on either his hip, shoulder, or back for a fair call; 3 throws needed to win the match. Illegal acts were things such as biting and genital holds (ouch), but other painful moves, like breaking your opponents fingers, were allowed.