Dueling Shows: Several shows on rival networks tried to dethrone CBS's Sunday evening cornerstone:
In the early 1950's, The Colgate Comedy Hour on NBC was a very strong competitor, even managing to surpass the "big shew" in ratings for a while, but eventually Ed Sullivan prevailed. note Interesingly, Dean Martin and Jerry Lewis, the most popular of the Colgate hosts, were guests on the June 20, 1948 premiere of Toast of the Town.
In 1956, NBC gave dethroning Sullivan another try by scheduling Steve Allen's new variety show directly against him. They gave up by the 1959-1960 season, when they rescheduled Allen to Mondays at 10, but their show still managed to snag Elvis Presley before Ed Sullivan could.
In 1964, The Hollywood Palace stepped up as ABC's answer to Ed Sullivan and proved to be a modest success, lasting until 1970, one year before Sullivan got cancelled himself.
Topo Gigio is an Italian mouse puppet who made regular appearances on the show, but became a superstar in Latin America thanks to his long running variety show which had various incarnations beginning in the 1960s up to at least the 1980s.
Canadian comedy duo Wayne and Shuster holds the house record for most appearances with 58 shows.
British bands, especially The Beatles, were warmly welcomed on the show.
Screwed by the Network: The show became one of the casualties of The Rural Purge in 1971. Although Sullivan was angered enough with CBS to refuse to do a proper finale, he hosted occasional specials for them until his death three years later.
Screw This, I'm Outta Here!: Bob Dylan was slated to make his first nationwide television appearance on the show in 1963, but walked out when the show's producers told him he couldn't sing his intended song, "Talkin' John Birch Paranoia Blues", due to its then-controversial references to communism.
Writer Revolt: There have been a few incidents of performers going against Sullivan's wishes:
Bo Diddley made an appearance on November 20, 1955. He was supposed to perform "Sixteen Tons", but played his eponymous hit instead due to misreading the cue card. Sullivan got furious and banned him from future appearances.
Buddy Holly, for his second appearance on January 26, 1958, was asked to switch out "Oh, Boy!" for another song, but refused due to having already told his hometown friends that he would perform his hit. This, combined with the rest of the Crickets being absent from the afternoon rehearsal, made Sullivan mad enough to cut his set from two songs to one and attempt to sabotage his performance by turning off the microphone on his guitar amp. Holly fought back by singing and playing as loud as he could to show the audience that the technical fault wasn't his. In spite of this, he was invited back for a third appearance. note Sullivan also butchered "Holly" into something like "Holland" while introducing him; while he had notorious difficulty with names, it might've been done on purpose.
When The Doors performed "Light My Fire", they were told to change the line "Girl, we couldn't get much higher" due to its alleged drug reference. The band eventually relented, and performed it accordingly in rehearsal, only for Jim Morrison to sing the original line on the air.note However, despite what the movie might claim, Morrison actually just sang it normally; i.e., like he did on the recorded version.