Possibly a garden - growing lesser known varieties of fruits can veggies is something I find interesting.
Or maybe making a traditional bow. Identifying types of wood, reading the grain, and turning it into a bow is interesting. I think most people have this concept that wood is this rigid thing, but seeing a traditional bow on a tillering tree is something else.
Making an (archery) bow is one of the most challenging woodworking projects of all --- removing 1/1000 of an inch of thickness from the back (evenly) will change the draw weight by 1 pound, and when the stave is first roughed out, there is a single point in the structure which is the weakest which defines the maximum possible draw weight for that bow --- that is, until one tries making arrows, as the old saw goes:
>Any stick will do for a bow, but an arrow must be perfect.
I've made a couple --- one of my most successful was a Decurve-reflex hickory-backed hickory Flatbow:
I was going to say the same thing, but with non-edible plants. I grow succulents and cacti, which are beautiful and extremely unique (seriously, the bear paw succulent is the CUTEST THING, and a String of Pearls has a window in each pearl showing you how much water is in it!).
It's so satisfying to watch them grow and to show progress... even if I have killed a few on accident.
Or maybe making a traditional bow. Identifying types of wood, reading the grain, and turning it into a bow is interesting. I think most people have this concept that wood is this rigid thing, but seeing a traditional bow on a tillering tree is something else.