Hmmm, electronics, photography, astronomy. Very popular here too. Too many cloudy nights and city glare for skywatching, but I combined two and built a series of radio telescopes. However, all can be done at home, in the winter and alone if required. As you know, I write, Practical Wireless and Radcom, in the main, but many other, mostly science-based, for instance I just made my first microwave radio system, and transmitted my voice across the room, with no prestidigitation, hidden assistants or optical illusions, and at no time did my hands ever leave my arms!
Then there are railways, of all sizes, industrial history, real ale, reading, (NF) listening to music, aviation, that'll do for now…