The Energy Museum on Wheels is coming to Bethel.  The 50-foot tractor trailer features a bicycle that can be pedaled to light up a light bulb.  The Town of Bethel in cooperation with HeatSmart Bethel is hosting the energy fair on Saturday.  Residents will be able to meet the new Bethel Sustainability Commission, visit the Energize CT Mobile Unit filled with kids’ activities and learn about solar, geothermal, insulation and other topics.  Visitors will also be able to test their energy trivia knowledge at the HeatSmart Bethel booth.  The event is Saturday at 1 School Street from 10am to 3pm.