Jimmy Fallon is classic.  He was always laughing in Saturday Night Live skits.
Jimmy Fallon
James Thomas Fallon (born September 19, 1974) is an American-Irish comedian, actor, television host, singer, writer, and producer. He is known for his work in television as a cast member on "Saturday Night Live" and as the host of late-night talk show "The Tonight Show Starring Jimmy Fallon" and before that "Late Night with Jimmy Fallon". He grew up with an interest in comedy and music, moving to Los Angeles at 21 to pursue opportunities in
screeching along with a bagpipe with castmate Jennifer Aniston sitting on the couch beside her and clearly trying to keep from laughing. The "Saturday Night Live" sketches featuring Debbie Downer (Rachel Dratch) are also notable for corpsing. Jimmy Fallon is also known for breaking character by laughing on "Saturday Night Live." Perhaps the most famous examples of this are the appearances of Bill Hader as the "City Correspondent" Stefon on SNL's "Weekend Update". The jokes were often rewritten between dress rehearsal and broadcast, so