Something is Intrinsically good if it is good even if it doesn't help anyone or make anyone happy. It's not good for what it does, it's good for just for being.
Life is sometimes said to be inherently good, and therefore should be protected even when the person possessed of it seems to be more bad than good. Art and beauty are also sometimes said to be good; the last person on Earth shouldn't destroy the Mona Lisa when he is on his death bed. It is good even if no one is around to see it.
God is also often said to be inherently good, even when He's turning peoples' wives into pillars of salt. Of course, God is often thought to be the source of 'good'; "If God does it, then it is good. How do you know? Because it was God who did it." This generally would be interpreted to mean that God is inherently good: to put it simply, "God is being God", "everything God does is good", "therefore being God is good", "therefore God is inherently good".
Knowledge and truth are also often cited as inherently good stuff.
Compare to inherently bad.