Awesome sauce. Per the LNJF Youtube page, here is the instrumentation:
Jimmy Fallon - wood block, Casio keyboardBrilliant.
Robin Thicke - spoons
Questlove - wooden clacker
Mark Kelley - kazoo
Kamal Gray - xylophone
James Poyser - melodica
Captain Kirk - ukulele
Tuba Gooding Jr. - recorder, banana shaker
Frank Knuckles - cowbell
Black Thought -- maraca