In a classic New England clambake, lobsters, clams, corn and potatoes cook in a rock-lined pit. Smoke and steam from hardwood coals and seaweed create incredible briny, sweet-smoky flavors. A terrific weekend activity, it requires some planning. A few key points:Most public beaches prohibit fires, even if the clambake is on a private beach; ask the local fire, parks and health departments if any permits are required. Keep a fire extinguisher and a large bucket of seawater close by.Avoid flooding your pit. Plan the clambake for low tide. To ensure the water table is low enough, dig a small, two-feet-deep test hole. If the hole is still dry after an hour, dig your pit.Be sure to get the right-sized rocks: too small and they'll lose their heat too quickly; too large, and they won't heat through.Don't use just any seaweed. The pockets of water and air in rockweed create the necessary steam and flavor.Hold all the ingredients in coolers while you build the pit and fire.