Writing! Let your imaginations take you places. You could create stories on things and events that have affected you or helped you, write about the memories!!!
As of this morning, I am hooked on Duolingo! Already I am 1% fluent in French. Hoping to learn the word for ladies room before our June 2017 trip.
Yay! Happy you found a hobby! 
I, original poster, have not found a hobby, but a hobby found me. I’ve been asked to write a book review. It"s due in a month, so maybe after I’m done, I’ll go back to doing even more writing, I used to do a lot for a hearing loss organization’s magazine. That’s what the book review is for, though a different organization and magazine than before. Of the volunteer work I have done before, the writing was the most fulfilling. It was fun to see the articles published. And it satisfies my creative requirement. I still might sign up for an art class too, though…
I hear that you can even get paid for writing. Just a rumor. 
Lol, sign me up! @VeryHappy
OP, you like the ocean - start a reef tank! Even a 10g can look good.
^^Only if you want to look at expensive dead fish. Keeping a reef tank alive in 10 gallons of water is nearly impossible.
Saltwater fish keeping is an expensive, involved hobby, and not for beginners unless you want to be scooping $200 flame angels out of your tank every morning.
Been there, done that, have the defunct 250 gallon tank sitting in our basement (anyone want it?). I do have a nice 75 gallon freshwater running in the kitchen filled with a few big oranda goldfish. That’s a good place to start if you want to do fishkeeping as a hobby. Just remember-bigger is easier. Water goes bad very fast in a small tank.
A friend of mine does geocaching. Started as an activity with her kids, and now she and her DH do it all the time.
+1 on salt water aquariums being an complex and expensive hobby. A former coworker had a huge tank and many fish, and lost almost all of them when we had a five-day power outage a few years ago. He was crushed and couldn’t bear to start over from scratch. Had been doing it for years.
I quilt, do Judaic fabric art, photography, make jewelry, read history/politics and exercise. I like gardening, too, though I’m not sure my involvement meet the level of a hobby.
All reefkeepers started somewhere It all depends on how much time one is willing to invest in learning. I have been reefing for 15 years, and it is a great hobby.
What do you do when your out of town? Do you have to hire a fish tank babysitter?
I do :), but not so much for the fish (there are autofeeders). We have a full blown reef with stony corals, they reqiure more care. In general, this hobby evolved so much in the last 20 years that it became much, much easier and foolproof. I can go away for a week and not need a tanksitter.
My dad kept a salt water tank when I was growing up. We went to the beach and got the water, seaweed, crabs, small fish and whatever else we could find. He’d keep it about a week and then we’d dump all the animals back at the beach and let them go. Sometimes we’d fill the tank with canal water and do the same thing. It was fun and cheap. And we didn’t kill anything.
I frogsat once… I kid you not. A coworker found some tadpoles in a puddle in the business park… Put them into a cheap aquarium adapted for amphibians. They turned into frogs! When he needed to travel, I volunteered to take care of them. A frog will only eat a moving prey. Feeding the little herd of frogs was hard work!
My hobbie now is to keep active and to try and do as many things I’ve always wanted to do.
This includes traveling to many places, including many of the National Parks in the US. Driving a skidoo. Happened to be in the ocean, but would gave enjoyed a lake. Preferred actually. Kayaking and snorkeling often in many places. Going to Broadway plays in NYC and visiting the MET, 9/11 museum, MOMA, etc, as often as possible.
Volunteering, including a free homemade soup give away program, Jan- March, at our church that I have been involved with for 3-4 years with.
I had hobbies in the past such as gardening, photography, antiquing and camping. Also use to do a lot of biking. Still do all, to a lesser extent. Although, one of my favorite, camping, I have not done in quite a few years. Pushing my H to start again. Still gardening, but it is getting harder. Spending a day gardening, planting, digging, pruning, is VERY tiring. Never mind the bruises and scratches. So pulling back on this.
Ironic about the fish tank suggestion. I think I’m about to inherit my son’s freshwater tank in a week. Voila! Hobby! We haven’t yet discussed what to do about it. (He’s been away camping.) A fish tank is allowed at his college but he is in a triple. I don’t think it will fit, and I’m sure the bubbler will drive his roommates crazy at night.
@gouf78 that’s the only way I’d do a marine aquarium now. Ties in nicely with the retirement thread that puts me and H on a boat in the ocean or right on the beach.
I’ll have you know I have made one. hundred. dollars. from writing, this year. I know, I know, seems crazy–and it’s only August!
50 from a short story, 50 from an essay–which went small time viral in a literary kind of way–shared by some big names! So you can see that this career is really taking off! 
My dream job is to be a writer
My part-time job in my semi-retirement is editing and writing employee benefit materials. I have decades of expertise in benefits and extraordinary skill with writing and editing (if I do say so myself). Plus, I get to work from home. I couldn’t have found a better gig for this time of my life.
And the pay is excellent.