MARBLEHEAD – Local residents had some prize-winning ideas on energy saving from a contest run at the Marblehead Go Green Day Fair in April.The fair was sponsored by the League of Women Voters and the contest was sponsored by the selectmen. Kathy Leonardson came before the selectmen Monday to introduce the winners.One of the most ambitious was “Dimmertime,” proposed by Michaela Griffin.The winner of the student portion of the contest would like to see local residents turn off their electrical appliances for an hour each Tuesday at dinnertime.”This project is not just for saving the earth, it is for letting families spend time together,” Griffin said in a description of her idea. She already has a Web site promoting her idea, www.dimmertime.org.”I hope (this idea) starts here in Marblehead but spreads throughout the country – maybe even the world. Imagine all the energy that could be saved and all the great conversations that families can have.”Energy-saving was a family affair for David Ginivisian and his daughter, Josephine, 5.Ginivisian won first place in the adult category for his idea, a town bylaw outlawing leaf blowers.”The noise is quite a nuisance, there are energy savings with the gas or electricity used to run them and it’s healthy to get out and rake,” he explained.Josephine, who lost her first tooth Wednesday evening, proposed that people sweep instead of vacuuming. Her idea was voted “most creative” by the judges.Christine Cudihy and Emeline Walker won co-first place in the adult category for proposing that the town post recycling barrels at parks and beaches all year long, instead of just July and August, to make recycling more accessible.