Portland is hosting a two-day regional gathering that’s showcasing dozens of projects tied to the creative economy. The Creative Communities Exchange is being held Thursday and Friday at the Maine College of Art and other downtown locations. It’s being attended by more than 250 people who work on creative economy initiatives for businesses, nonprofits, research organizations and government across New England, as well as other states and Canada. The event features more than two dozen workshops, networking opportunities and an awards ceremony. The event is put on by Creative Portland and the New England Foundation for the Arts of Boston. It builds upon two previous creative economy events held in western Massachusetts in 2011 and in Providence, R.I., in 2009.