I've considered actual school, or at least taking a class. Barnard lets alums audit. I always wanted to take symbolic logic or music theory, or build on the pitiful amount of Russian I learned in high school. But even though auditors are exempted from pressure and work, do I really want to have to be somewhere on a regular basis? Especially when the weather gets cold. I'd feel ancient next to 20-year-olds. Plus the list of closed courses seems to exempt just about everything.
There's also adult education, available all over the city. I did the MEA Saturday morning film series for a few years and loved it, except for the horrible hour that made me miss so much it wasn't worth it. I seriously considered going back, but instead joined IFP/Museum of the Moving Image and now need to make that worth it. I've seen exactly one movie since joining in June, but there are some promising items on the calendar.
Music is another strong possibility. I took a chamber music workshop at the 92nd Street Y for 2 years in the late 70s and really enjoyed it. I even started private piano lessons again with the teacher (now deceased). But I couldn't fit in actuarial studying, working, AND keeping in practice so that eventually faded.
I have a lot more free time now. But I hate being locked in to anything. I want to take on less work and read, read, read, my activity of choice.