As Jimmy Fallon prepares to take over the helm of "The Tonight Show," take a look back at nine of his funniest moments on "Late Night." Slow Jamming the News with President Obama In April 2012, President Obama helped Fallon and Tariq "Questlove" Trotter slow-jam the news.
In February 2013, Brooke Shields (second from left) helped Jimmy Fallon spoof "Downton Abbey" in a sketch called "Downton Sixbey" (named after Studio 6B in 30 Rock, the home of "Late Night").
Jimmy Fallon is known for his dead-on musical impressions, including an uncanny imitation of veteran rocker Neil Young.
One of Fallon's cleverest characters is "Tebowie": a mash-up of rocker David Bowie and quarterback Tim Tebow. Here Tebowie appears in Ziggy Stardust regalia in March 2012.
Jimmy Fallon and Rachel Dratch parodied MTV hit "Jersey Shore" with "Jersey Floor," set on a magical floor of 30 Rock inhabited by young New Jersey Italian-Americans. Here they are joined by real "Jersey Shore" cast members in September 2011. From left: Jennifer "JWoww" Farley, A.D. Miles, Dratch as "Drootchie," Fallon as "J Bro," Nicole "Snooki" Polizzi, Deena Nicole Cortese and Sammi Giancola.
Aided by house band The Roots, Fallon (left) and Justin Timberlake perform the fourth installment in their acclaimed "History of Rap," a bravura medley of hip-hop classics, in March 2013.
In March 2013, first lady Michelle Obama joined a bewigged Jimmy Fallon to perform "The Evolution of Mom Dancing," featuring such moves as the hip bump.
In December 2012, Mariah Carey joined Fallon and The Roots to perform a special rendition of her holiday hit "All I Want For Christmas Is You" using classroom instruments.
In July 2012, Charlie Sheen joined Fallon on "Late Night." The "Major League" star and Fallon stepped into a batting cage for some friendly competition.