The Puna District is wild in every sense of the word. The jagged black coastline is changing all the time; the trees are growing out of control, forming canopies over the few paved roads; the land is dirt cheap and there seem to be no building codes; and the people—well, there's something about living in an area that could be destroyed by lava at any moment (as Kalapana was in 1990) that makes the laws of modern society seem silly. So it is that Puna has its well-deserved reputation as an "outlaw" region of the Big Island.
That said, it's well worth a detour, especially if you're near this part of the island anyway. Volcanically heated springs and tide pools burst with interesting sea life, and some mighty fine people-watching opportunities exist in Pahoa, a funky little town that the "Punatics" call home.
This is also farm country (yes, that kind of farm, but also the legal sort). Local farmers grow everything from orchids and anthuriums to papayas, bananas, and macadamia nuts. Several of the island's larger, rural, residential subdivisions are between Keaau and Pahoa, including Hawaiian Paradise Park, Orchidland Estates, Hawaiian Acres, and Hawaiian Beaches.
When dusk falls here, the air fills with the high-pitched symphony of thousands of coqui frogs. Though they look cute on the signs and seem harmless, the invasive frogs are pests both to local crops and to locals tired of their shrieking, all-night calls.