If this one doesn’t put a smile on your face, someone better call an ambulance or a preacher.  Over the weekend, Wilco released the video below (filmed by Zoran Orlic) of  Wilco, Nick Lowe and Mavis Staples rehearsing The Band’s The Weight backstage at the Civic Opera House in Chicago in December.  The video starts off sorta lazy like rehearsals are wont to do, and then Mavis just can’t help herself.  Having been there with her family for the all-time version captured by The Band and friends in The Last Waltz concerts and film in 1976, Mavis knows the power of this great song.  She seems to sense the need and so starts conducting matters and entreating the fellas vocally and then singing in hearts.  ‘Dem ‘dat knows it, feels it.  And we love everything about Nick Lowe here.  Starting with the smile that takes him over at 0:14, the momentary bobble to begin his part at 1:32, Mavis’s and Tweedy’s smiling acknowledgment at 1:43 of Lowe’s nicely subtle, but commanding vocals, and then the return of Nick’s smile at 4:00 along with his involuntary head-bobbing.  Jeff Tweedy Dankos in on the song perfectly at 2:20 and kills, and the band plays on and Mavis takes matters back over.  Magical things can happen when you least suspect it, and especially when marvelous Mavis Staples is making them happen.  Too dang good.