This may not be the definitive recipe, but it sounds good enough for hot weather. If you're inventive you'll figure out how to make it on your grill outside with indirect heat so it cooks slowly. But this is an oven version. I think if you had one of those electric turkey roaster things or a big crockpot, you could put it outside on the porch to cook so your kitchen doesn't get all heated up.
1/4 cup brown sugar
1/2 - 1 teaspoon cayenne pepper
Coarse salt
Ground pepper
Combine these ingredients to use for a rub or use another rub recipe or boughten rub.
3 pound boneless pork shoulder
1 1/2 cups cider vinegar
4 garlic cloves, minced
1/2 cup water
Favorite barbecue sauce
Preheat your oven to 350 degrees. Put the pork in a 5 quart dutch oven or large heavy pan and rub with the spice mixture. Combine the liquid ingredients and pour over the pork. Cover pot and place in the oven on the lowest rack. Bake until the pork is very tender and pulls apart easily with a fork, about 2 to 2 1/2 hours. Transfer it to a work surface and reserve the pan juices. Shred the meat with two forks. Moisten with pan juices if desired. Serve on soft sandwich rolls with your favorite barbecue sauce and plenty of napkins.