At 48 I bought a TIG welder. It was difficult at first, but now I can weld steel, aluminum, and stainless and it usually doesn't look like crap. It's very fun.

Then last year at 49 switched from right handed to left handed guitar since I'm left handed and was never very good right handed. I've been practicing every day for at least an hour for 11 months now and enjoy it a lot.