Now in its 8th year, Fairfield County's Giving Day is being held today.  Nonprofits and other organizations are seeking donations during the region's biggest philanthropic event.  Among those asking donors to step up to fill various needs are Greater Danbury area libraries, land trusts, arts organizations, mental health groups, those addressing food insecurity and the Women's Center.  Sandy Hook Volunteer Fire & Rescue says every dollar donated to their department will be used for equipment, apparatus, maintenance, training, and the like.  The one-day, regional effort harnesses the collective power of individuals, businesses, and others to transform how people think about, talk about and participate in giving.