'Rainbow' singer teams with 'Tonight Show' band for acoustic spin on Animals' classic
'Rainbow' singer also joined Fallon, Anthony Anderson, NPR's Terry Gross for late-night version of 'Password'
Billy Crystal, Keegan-Michael Key also appear in 'Tonight Show''s recurring "Camp Winnipesaukee" bit
Thrash metal giants also share their favorite tour stories on 'Tonight Show'
Pete Townshend busts out triple windmill during two classic songs
Wiig and Fallon spun a random assortment of unrelated words into amusing medical comedy on 'The Tonight Show'
Actor and host wear big wigs and fake mustaches to determine truth behind Questlove's unbelievable facts
Rapper also taps Kilo Kish, Ray J for charged performance of new track "Love Can Be..."
The Roots played famous tracks from Oasis and Snoop Dogg as Williams and Fallon scrambled to identify them
Singer also talks escaping celebrity life by returning to New Zealand, being freaked out by 'Twin Peaks'
'Malibu' singer also talks fear of dying mid-monologue from smoking too much weed, 'hillbilly' family vacations, taking on 'Voice' coach Blake Shelton
Pop star delivers remarkable vocal renditions of two new country-tinged songs during 'Tonight Show' takeover
Former One Direction singer, 'Tonight Show' host teamed to tackle "Witness the Fitness," "Quickly Clicky Pens," "Stepping on Toes"
Seductive track highlights new duets album from Fleetwood Mac duo
Duo celebrate Swae Lee's birthday with hypnotizing rendition of new single