600 years before Christ and half a world away, Gautama Buddha promulgated a moral and ethical code which became Buddhism. It developed and expanded to the point, 265 years before the birth of Christ, when it led to the establishment by the king of the world's first major Buddhist state, of free hospitals and free education and also the first recognition of human rights.
First of all, I don't think that Buddha is a fantastic example. After all, Buddha was the one that told his followers to believe only their own experiences, not what others told them. So even if Buddha did 'promulgate a moral and ethical code', that code only applied to him (because of course he 'experienced' it-- after all, when he was a monk he nearly beat himself to death. That of course must have played a part in his own personal 'ethical code'). The followers of Buddha can't do what Buddha told them to do for the sole reason that Buddha told them not to do it just because Buddha told them to do it. The whole Buddhist system of beliefs is founded upon personal experience, and according to them you can't believe anything unless you've experienced it yourself. So a good Buddhist can't say "Well, Buddha said that murder[or you-fill-in-the-blank] is bad, therefore it is bad". For the good Buddhist, the attitude must be, "I haven't experienced murder to be bad, so I don't believe it to be bad."
And it still comes back to the question: what is good and evil? Who defines it? For the Buddhist, you 'create your own reality', and that includes your morals--what you believe to be good or bad. The atheist is in the same boat, since there is no 'higher authority' to define good and evil. The ultimate authority is the human mind, which we all know to be finite. (at least, I'm assuming we all know that...... ;)