As the owner of Arthur W. Good C.P.A. Inc. in Seven Hills, he provides tax planning and accounting system design services. He also is a Cecropia moth breeder, the "guy that figured out how to raise moths" free from disease and safe from predators. His unusual fascination with moths aside, Mr. Good is far from unique in his drive to make a business out of his hobby. But he does typify the kind of entrepreneur who manages to make money off of what was once just an enjoyable pastime. "These folks back into the business, but still have 'keys' to a business," said Tracey Messer, an organizational behavior doctoral candidate at Case Western Reserve University's Weatherhead School of Management in Cleveland.