I'll buckle down on my mandolin playing, and it's time to pick up the fiddle and give it a good effort.
Read more.
Let's not let all that coding experience go to waste: I'll go hunt down an open source project that I could make some good contributions to, and then devote a good chunk of time to that. Or write something new that the world could use.
But beware: "if you didn't need money" is a pretty loaded phrase. As I stare down the firehose of money and realize it will soon produce only a trickle, if that, I still ask if we have enough even though we're probably better off than the majority of retirees (if various sources are to be believed). Because there's "don't need an income" and then there's "won the startup lottery, and my kids won't need an income", and we are firmly in the former category. :-)