William and Nadine McGuire moved to Minnesota about 15 years ago, and have emerged as leading donors to the arts in the Twin Cities. “The McGuires’ burst of generosity just since July has left observers giddy: $10 million to the University of Minnesota, $10 million to the Guthrie Theater and $1 million to the Children’s Theatre Company. Other recent Twin Cities giving by the McGuires and their family foundation, for which details were not revealed, bring their total giving to more than $40 million, William McGuire said Thursday.”