Since you're looking for ideas, I'll just list a lot.
Walking, walking the dog, solving obscure software, statistical, or other problems, working on the house (renos) and yard, playing board games with the kids, ballroom dancing, Argentinian tango, and reading.
Before I got married, I did a lot of hiking, canoeing, calligraphy, listening to blues at the bar, meditation, being involved in a few clubs, organizing things like potlucks, and working on the acreage.
I'm thinking of starting to tinker with electronics again, maybe take up drumming. The kids are old enough that canoeing/kayaking trips are possible.
Scotch is good. Oh yeah, I used to brew mead, beer, and root beer. The mead varied a lot in quality and the root beer had a tendency to explode and hit the ceiling but was very good.