What Does it Mean to be "Born Again"?

...Unless one is “born again.”  This phrase carries great meaning no matter what Christian denomination you come from.  The meaning of the phrase certainly changes depending upon your particular belief system, but the power of the phase remains intact. To be “born again” in all cases implies one of the most significant spiritual changes any person can ever experience.  So when does being “born again” happen and what does it really mean?  Does this spiritual change happen when one is baptized as an infant or when one commits their life to God through Jesus or when one is baptized as an adult or when one dies?  Is this spiritual change a prepaid one way ticket to heaven or an opportunity for power and control in your present life, or is it a sober and humbling opportunity to sacrifice all that you have and all that you are?