Siblings Rufus and Martha Wainwright, spawn of Canadian folk legends Loudon Wainwright III and the late Kate McGarrigle, are jointly touring in support of new solo releases: Rufus's All Days Are Night: Songs for Lulu, an uncharacteristically austere album, focused on piano and voice; and Martha for a live, French-language tribute to Edith Piaf. Chances are good they'll perform together as well, just like old times. Tonight, Saturday, Aug. 7, at 8 p.m. Music Center at Strathmore, 5301 Tuckerman Lane, North Bethesda. Tickets are $46. Call 301-581-5100 or visit strathmore.org.