Just as the ducks at the park are free, there is also no legal requirement to answer the phone in particular way. Hit folks with a, "Ahoyhoy", "Howdy", "Whats good brother?", or for the more adventurous, "Ralphs Roadkill Cafe. You kill it, we grill it."
Was always my favorite. Probably because I would love to take a restaurant a bucket of fresh-caught bluegill and come back in a couple hours to dinner. Filleting all those little bastards is a pain...