If no one controls this then how can you be sure it is stable?
There is a bigger discussion around this point - it implies a that a currency controlled by a government is stable.
Stability is not determined by a government, no matter what you may believe. The value of the Euro or the Pound or any other currency is determined by the general consensus in the market that the currency has a certain value. When markets turn against a currency it can be a problem. Note for example how the US dollar collapsed to half its value against the Euro couple of years ago.
It is the same for Bitcoin, except that what you need to consider is that Bitcoin is still very new and early valuations of new technologies are naturally unstable because markets do not know them very well and can get spooked easily - hence the volatility. This will become less and less as time goes on.
How is it regulated and most importantly how is it valued?
The system is self regulating, but it depends on what you mean by regulation. Regulation is not always necessary for successful technologies. Is facebook regulated? Is amazon? Both have issued their own form of currency, and nobody talks about regulating them.
What sort of legal framework do you think is suitable to "regulate" bitcoin? Even the regulators in most countries are issuing notices stating that they do not have the authority to regulate Bitcoin. Note they are not banning Bitcoin. This means exactly what it says, and doesn't say.
I'm having a hard time grasping the idea of not being centralized and
regulated somehow… can someone game the system… blah blah blah etc!?
I'm not surprised you are having a hard time. You probably do not know enough either about the Bitcoin protocol, the technology behind it, how markets work, how markets can be gamed (or not).
I can't answer a vague question on this but I suggest if you think of a specific situation where something might happen, post your question and someone will answer.