Great question! I wish I could say gardening was one of mine, but it's actually one of the things I avoid and then feel guilty about. I have a spectacular weed garden out back. Want to come over and do some planning in my backyard?
My true therapy activities are reading and hiking (alone; it's enjoyable, but not relaxing, if I have to talk to people). I would put sleep, since I really need quite a lot of it and I'm very cranky if I don't get it, but since I'm unconscious while I'm doing it, I don't think it counts.
I used to watch telly quite a bit, but that never seems to happen anymore. I've got out of the habit over the past few years, since I started a second degree, and have homework in the evenings. Nowadays I'd rather sit at the laptop and binge-read articles about the Donald Trump trainwreck.