How blue is your grass? Niwot’s own Pete and Joan Wernick, who perform in free concerts on Saturday, October 7, and Sunday, October 8, at the Denver Performing Arts Complex, combine masterful acoustic pickin’ with heartfelt vocal harmonies; it’s a one-two punch that has earned the pair the honorary distinction of Dr. and Nurse Banjo.: Although Pete holds a Ph.D. in sociology from Columbia University, his reputation comes as much from the alchemy he can produce on a five-string as any piece of sheepskin. Widely known as a core member of Hot Rize (as well as its daffy alter ego, Red Knuckles and the Trailblazers), the good Doc W. has garnered his share of national praise since his mid-’70s involvement in the groundbreaking Ithaca-based progressive bluegrass outfit Country Cooking. Nurse Nondi: (Joan) soothes like Florence Nightingale in your darkest hour. As grassroots hostess to Old Grass, GNU Grass,: a KGNU specialty show since 1978, her soulful voice lends itself effortlessly to ballads about broken hearts, mining-town disasters and human folly. On the heels of their first duet CD, Windy Mountain -- a tribute to traditionals including I’ve Endured,: Caves of Jericho: and Be Proud of the Gray in Your Hair: -- the pair puts on a banjo-induced medicine show, a clinic bursting with lickety-split solos and backwoods laments. Best experienced live, they satisfy both mind and spirit, like an impromptu history lesson or a simple, hearty meal from a cast-iron skillet. Lively, bluesy and beautiful, the Wernicks’ sound is more than enough to remind you of life’s good things.