Lisa Green, crossing guard at the corner of Longfellow and Maine streets in Brunswick, has a wave or a smile for nearly every passerby. Her habit of wearing funny hats began last year when serving near Jordan Acres School.   "I was clipped," she said, "and it hurt!"  The guy {who hit me} kept saying that he didn't see me -- so I decided to start making it impossible to not see me." She added, " My best hats come out at Halloween!"  Photo by Roger S. Duncan.