Pirates versus Ninjas
“Ninjas might fight better, but I'd rather party with pirates.”
“Ninjas ARE better at killing people, but pirates are better people persons”
Pirates versus Ninjas was one of the great conflicts that make up world history. It kind of happened when some pirates sailed to China and got really drunk and decided they were going to try and eat some sacred scrolls that belonged to the ninjas because they read about it in Revelations while making the Black Spot last time they wanted to kill their captain. This made the ninjas REALLY REALLY pissed off.
So, the ninjas took down the Jolly Roger flag and put up somebody's underwear on the flagpole instead. The pirates didn't notice, so that plan failed.
Several years of unstable peace followed as the pirates sailed to other places and eventually came back.
The new captain decided he just didn't like ninjas, and the ninja warlord master decided he just didn't like pirates. So they decided to begin their incredible battle of ultimate PWNAGE.
Rock, Paper, Scissors
Ninjas won every single one of the first several hundred rounds of rock, paper scissors.
Go Fish
The Pirates won at Go Fish.
Farting Contest
Singing
Anything involving actual fighting
Ninjas.
The pirates all died. That's why the Pirates of the Caribbean movies ended but they're still making Naruto.