Fishin'.
 

I think we should be able to make a net (like we plant corn, take it to a blue-roof mill, not red-roof), take it to it, it makes twine, you go to the crafting place, then you make a net. It takes about 20 pieces of twine to make a net, you go to Hotaru, place some minerals in the water, similar to the shop thing, and then you drop the net over the mineral rocks the same way, THEN you wait for fish to come, finally you press the A button and catch all the fish. This would make fishing for many at the same time easier.

The ides isn't too bad, but being able to catch many at once would lower their value... Also, what do you mean with the minerals? Ans you could make twines from cloth - as carpets and lines are made from it...