The Roots and Elvis Costello are two tireless acts who are so in love with collaborating. These days you see Elvis join in jams on his Spectacle interview/performance show. Questo et al do it all the time at their Late Night digs, and if you were lucky enough to have a ticket to Dirty Projectors' tour-closing show at Bowery last night, you saw Ahmir, Captain Kirk, and another Root join the band on "Stillness Is The Move" (Byrne showed up too for "Knotty Pine," video of all that TK). As for Mr. Costello: Friday night he stopped by Fallon's place to do the good work of promoting Spectacle's Season 1 DVD release and Season 2 premiere (airs 12/9); the day before, he battled a bad throat to try and out talk Stephen Colbert. Both netted collab jams, of course: EC and the Roots did "High Fidelity," and Costello let Stephen take the vocals on their "Cheap Reward" duet at the Colbert Report desk. (Colbert was born to sing "lip service, that's all you'll ever get from me" to a studio audience.) Enjoy 'em via embed: Continue reading Elvis Costello Jams With The Roots, Colbert...