This August, a coast-to-coast concert tour takes on the everlasting theme of romantic love. Join host Garrison Keillor, Nickel Creek’s Sara Watkins, the Guy’s All-Star Shoe Band, and sound-effects man Fred Newman for tender duets and ballads, poetry (Poe, Shakespeare, Anonymous), stories of passion and marriage, and Mr. Keillor’s intermission walk through the audience for the sing-along of “Unchained Melody” and “Can’t Help Falling in Love with You.” All this and favorite elements of A Prairie Home Companion — Guy Noir, Dusty and Lefty, the News from Lake Wobegon — during an entertaining date night for all ages.