All signs point to big celebrations for Americans this Fourth of July even as sizzling temperatures are triggering heat warnings for millions. Travel records are projected to fall as people gather for cookouts, parades and fireworks. Some unique celebrations are also planned. In Down East, Maine, lobster boat races will be held off. In Philadelphia, descendants of the signers of the Declaration of Independence will ring the Liberty Bell. An annual tug-of-war contest is being held in California. And, of course, there's the annual hot dog eating contest in Coney Island, New York.