Well I didn't have a plan, but I did branch out in several directions and the one that took was playing music. I played in HS, dropped out in college to focus on engineering. After ~30 years of not touching my horn, I joined a band and now play in 2 concert bands and one jazz band (big band) and loving it!
I say this because I figure there are plenty of you who played a horn in school and this is an excellent program for mental and physical (breath control, attacks, etc) stimulation to keep you engaged while having fun and being part of a team. It also hits on the volunteerism as most of our gigs are free for public such as park events, holiday events, senior centers, etc.
I hope Richard doesn't mind if I hi-jack his thread to provide a PSA!
There is a program called "New Horizons Band" that has 170 bands in the US (actually more. I know of 2 more in the Atlanta area that are not on their map):
Interactive map:
http://newhorizonsmusic.org/new-horizons-groups/
Also google "community bands" for your area!
If you don't have a horn, or dig it out of the attic to find it is now green, you probably don't won't to buy one until you know you are enjoying it and also, you probably don't know what to buy. Most Band stores have ridiculously cheap rental programs designed to help parents of band students (they are hoping to sell a horn if your student wants to continue playing). This is a great way to go because they make sure the horn plays well (they won't end up with a horn sale if you quit because you get frustrated). It cost me $10/month to rent a tenor sax for the first 6 months and went up to $30/month after that!
One band I am in is subsidized by the municipal Government (and we play music at of their patriotic events). The other two cost $15/month (covers both concert and jazz band) to pay for rental of rehearsal/storage facility, music (including files and copy machine), Band owned gear (Kettle Drums, PA, Keyboard, etc), and the director is a part time paid position. So $180/year for fees.
One nice thing about the New Horizons Band program is the guy sitting next to you was most likely in your shoes a couple of years ago, so they are not going to get upset about a wrong note or two as you are getting your chops back. The important thing is to know what not to play in the concerts until you get on top of things. As TLSGuy likes to say "sins of commission are worse than sins of omission"!
When you start out you will see great progress as things start coming back to you. I had to ask the guy next to me some ridiculously embarrassing questions (like I had forgotten what the double sharp symbol was/meant). It took me about two years to fully get back the proficiency I had when I quit 30 years earlier. Now I am playing better than I ever had before I quit (in most ways - the years have given me a better sense of style/interpretation, but I now need to mark most of the sharps and flats on my music rather than attempting to remember what key signature I am in
).
Hope this helps anyone planning retirement. It has been great for me!