I think Pirates would win because they're just stupid enough to be used as a meat shield, but smart enough to use tactics, swords and guns. Ninjas are all stealthy and all, but I'm pretty sure they can't dodge bullets and cannon balls that well. Cavemen are just dumb brutes, and will probably run from the loud noises of guns discharging. Astronaughts won't last very long. Chuck Norris is just one guy. I'm sure he could single handedly take on a ship full of pirates but not while he's fighting Ninjas and Astronaughts.
Ninjas would win.. no need to explain, they just would. Besides explaining it would simply take away from the beauty and technique that no witness will ever live to tell the tale.
One hint though... a major contributing move is called "receive bacon" - no one can survive that move... it causes the blood in the recipient's boody to instantly congeal. It is nasty and painful and tasty all at once!
I agree with Shabs. Ninjas, would throw throwing stars and attack with swords. As good as Pirates were with firing muskets, they would really only get one volley before all the others would join in the penultimate orgy of killing. The only way for Chuck Norris would be if he hid while the others duked it out. But, Chuck being Chuck I don't think he'd hide. Perhaps the rest would view him as a threat and therefore gang up on him at the onset of destruction. Cavemen would run at the first sound of gunfire, like Diddly said. Astronaughts would slowly hop around and therefore would be shot immediately.
Ok.. humourous situation in which astronaughts could win this battle.. well let's see... I'm assuming both Pirates and cavemen are MEN.. and Chuck Norris, while god-like to some is likely a man as well.. and ninjas.. well needless to say they wouldn't let women amongst their ranks because they are zero tolerance for emotional outbreaks and no woman can shut them off competely.. but we know that you don't have to be a man to be an astronaught... afterall they had that nutbar who drove half way across the states to "be with her true love" who was married to someone else with kids... so clearly the only way astronaughts could win is if they were FEMALE astronaughts who put on a 3 stooges marathon on constant repeat... the result would be the men laughing themselves so long and hard that eventually they would become dehydrated at which point the fem-naughts could talk to them and the men wouldn't have the strength to walk away and/or ignore them.. so as a result Chuck Norris would muster JUST enough remaining strength to incinerate the universe... its not a straight out win, but it is as close as humanly possible for the astronaughts to NOT LOSE...
Or... how about Zuul from Ghostbusters, in the form of the Stay Puft Marshmellow Man, sees the battle raging between Pirates, Ninjas, Cavemen, Astronaughts and Chuck Norris. Thinking the astronaughts are like little mini-mellows, it attacks and kills all the other participants. Except, of course, for Chuck Norris, who died from laughing at the Astronaught's happy dance.
You're both wrong. The astronaughts, while slow, would attach a large scythe to the canadarm and use that to mow the competition in half. They would then be the samurai of space, and the canadarm, their huge, gore stained, katana.