If two people - neither of whom I know - are so pissed off at one another that they want to fight each other to the death and they are so stupid as to do it, I don't see why it's any of my business. Is S&M unethical behavior, and should it be legal? Because you own yourself and your body, and if you willingly enter into an agreement with another party to inflict harm on one another's bodies, what is the difference whether it's fighting or fucking?

That credo alone is sufficient to build an ethical system around?  The trend of this discussion is individuals arguing that credo alone is sufficient.

In regards to The Hunger Games, if one happens to see it ONLY has a a totalitarian government at work, one misses how the games themselves are structured and the message the writer was trying to discuss.  And the critiques aren't focused on free will, but barbarism.  A number of other stories have touched on the same subject:

http://www.salon.com/2012/03/14/what_came_before_the_hunger_games/

Rollerball in particular, is one.  It takes in a corporate run future, where the violent game Rollerball is the top sport:

http://www.imdb.com/title/tt0073631/

http://en.wikipedia.org/wiki/Rollerball_(1975_film)

The focus of these stories are on barbaric states societies can let themselves fall into, and their horrors. But hey, so long as no one is coersed, why be concerned about it? 

I do notice that you didn't answer my question ... Suppose an individual has experienced kidney failure and they need a kidney transplant to survive but (for a wide variety of reasons) the compatibility for a donor is low, would it be ethical for him to be able to force a healthy individual to give them their kidney knowing that they health of the healthy person would be significantly impacted?

I already stated that life, in and of itself, is not a right because everyone dies and your life ending does not mean that your rights were violated ... You do have the right to live your life free of intentional harm inflicted by others including, but not limited to, being murdered by someone else.

Now, you seem to confuse what someone has a right to do with something that is ethical for them to do. A person may be entirely within their rights and still do something unethical, but the fact that it is unethical doesn't eliminate that he has that right.

As for your murder cases ...

If someone is in a situation where they are aware of significant risks to other people, and they have the ability to prevent harm occurring to other individuals without suffering harm to themself, they have an ethical responsibility to interviene; but this doesn't mean that the person who risks harm has a right to their intervention.

First of all, Have you actually read the book Hunger Games?  Because it doesn't seem like you have a very good understanding of it.  First of all, they don't choose to watch it, they are forced to watch it under threat of death.  Also, they are forced to enter their name in more than once if they actually want to eat.  I mean, obviously the series ends with the people choosing to rise up and rebel, but I think they do that so that they can have the choice, not in spite of it.  

Also, if they had volunteered to fight to the death for fame and glory, how exactly is that different from somebody joining the military today?  People do volunteer to fight and die today and nobody looks at a soldiers death and says, that was unethical of him to volunteer and do that.  

Which it is.

Outside which.

I'm pretty sure killing someone else in a hunger games style enviroment would qualify as "One man's fist ending at another man's nose."

I was just looking over a few of the arguments and just wanted to point out something.
-The right to not be forced to pay for someone else's health care.

I mean it all sounds good to me, but ......isn't this already violated by mandatory Tax on EVERYTHING we buy and in many states our paychecks??? We have no say in the matter, portions of our money are being funneled into god knows what and we do not get to say "Hey, I want my portion of the tax to go to _____".

There are individuals that choose to enter the military, because they see no economic opportunity available to them.  The pick what they see as the lesser evil.  Pretty much you see this happen.  As economic times get worse, people are more willing to join the military out of necessity:

http://www.military.com/features/0,15240,204238,00.html

In regards to choose to watch or not, a lot of choices in life come down to deciding not to die or not.  People will feel compelled to pick a poorer choice over death.  What the discussion here has come down to is enshrining choice above everything else.  People will argue here that so long as I personally choose to do something, it makes it ok, so long as I don't interfere with other choices.  And it was a focus on liberty above every other value that will pop up in rights-based ethics system.  What you see in this is a blind spot to situations where someone could intervene to enable a person to not make a bad choice, but they don't.  By saying ethics is simply a case of not punching people's in the nose, it fails to address actual issues that could reduce what other values systems would see as evil.

There are individuals who argue tax is theft, and there should be no taxes.

If one person has the right to use contraception it doesn't violate another persons right to not use contraception (because of religion or whatever). And the catholic church as employer is no person, so the concept of personal rights doesn't apply here.

Both examples are again persons against non-persons. Again, if you prefer personal rigths it's clear which side wins.

And yes, rights of one side always can conflict with other rights. That's normal. We usually have priorities defined.