Portlandia stars Fred Armisen and Carrie Brownstein have been skewering rock's great clichés from the beginning — remember our October 2011 interview with the pair? — and they've had some impressive help along the way, from a ghostily materializing Jack White to a hot-airborne No Doubt. This week's forthcoming episode will feature cameos from gnarl-master general J Mascis and the SPIN Essential-dropping Dirty Projectors, both appearing in a sketch poking fun at the Pacific Northwest predilection for mellow music.At a "Battle of the Gentle Bands" in an Oregon park, Armisen leads a group called Featherwash whose droning folk-lite is helped along by DP main man David Longstreth. Next up is Bless the Barn, fronted by Brownstein and a shamanistic Mascis who strums faintly on an unplugged electric guitar. Their coup de grâce? Projectors Amber Coffman and Haley Dekle ringing a large bell with their kisses. They're all outdone however by Franny Wisp, who has an exceedingly gentle trick up her sleeve.Catch the entire episode on Friday night via IFC, and check out our new chat with Armisen, in which he queries, "What would Hüsker Dü?"