I do a 24 hour pulled pork.
Preheat your oven to 450. While you are waiting for it to heat, rub your pork butt with a dry rub. Use a packaged one, or mix a cup of brown sugar with a couple tablespoons of chili powder, maybe some garlic, some cumin if you like it, some cayenne if you want a little heat. For a smoke flavor, put a tablespoon of liquid smoke into the sugar mix. The sugar caramelizes, so the roast has a little sweetness, not a lot.
Put your rubbed roast in a baking pan with a rack, and put it into the hot oven. Immediately turn the heat down to 200 degrees.
Go to bed. Next morning, your house will smell great, but try not to eat the roast for breakfast. Instead, let it cook all day.
Take it out, look at the beautiful "bark" (crust), shred it up and serve on nice soft buns with bbq sauce.
I do these 2 at a time, because it freezes really well. (If you are only doing one, use a half cup of sugar.)