Backstage before the show, Jimmy, Mariah Carey, and The Roots grabbed some instruments you'd find in an elementary school classroom and stopped by the Late Night "Music Room" to sing Mariah's holiday classic, "All I Want For Christmas Is You." (instrument list below) Jimmy Fallon - wood block, tambourine, bass drum, kazoo Mariah Carey - vocals Questlove - wooden clacker w/ afro pick Mark Kelley - Fisher Price xylophone Kamal Gray - recorder James Poyser - melodica Captain Kirk - ukulele Tuba Gooding Jr. - kazoo Frank Knuckles - bongos Black Thought - sleigh bells Download Mariah's "Merry Christmas II You" here: http://smarturl.it/MCIIYou Subscribe NOW to The Tonight Show Starring Jimmy Fallon: http://bit.ly/1nwT1aN Watch The Tonight Show Starring Jimmy Fallon Weeknights 11:35/10:35c Get more Jimmy Fallon: Follow Jimmy: http://Twitter.com/JimmyFallon Like Jimmy: https://Facebook.com/JimmyFallon Get more The Tonight Show Starring Jimmy Fallon: Follow The Tonight Show: http://Twitter.com/FallonTonight Like The Tonight Show: https://Facebook.com/FallonTonight The Tonight Show Tumblr: http://fallontonight.tumblr.com/ Get more NBC: NBC YouTube: http://bit.ly/1dM1qBH Like NBC: http://Facebook.com/NBC Follow NBC: http://Twitter.com/NBC NBC Tumblr: http://nbctv.tumblr.com/ NBC Google+: https://plus.google.com/+NBC/posts The Tonight Show Starring Jimmy Fallon features hilarious highlights from the show including: comedy sketches, music parodies, celebrity interviews, ridiculous games, and, of course, Jimmy's Thank You Notes and hashtags! You'll also find behind the scenes videos and other great web exclusives. Jimmy Fallon, Mariah Carey & The Roots: "All I Want For Christmas Is You" (w/ Classroom Instruments) http://www.youtube.com/fallontonight