Short answers, pulled from the story.
The first edition of Top of the Pops aired on Wednesday, the 1st of January 1964 at 6:35 pm from Dickenson Road Studios in Manchester. Bill Cotton and Johnnie Stewart devised a strict set of rules that governed how the show would operate for decades to come.
Status Quo holds the record for most appearances by any group with 106 total visits spanning from Pictures of Matchstick Men in 1968 to The Party Ain't Over Yet in 2005. Cliff Richard appeared nearly 160 times making him the individual artist with the highest number of performances.
A Musicians Union strike between May and August 1980 forced the cancellation of live music performances across all eleven BBC orchestras for nearly three months. During this period viewers watched repeats of Are You Being Served instead of the usual musical content.
The last regular edition aired on the 30th of July 2006 after which the weekly series officially ended though Christmas specials continued annually. Edith Bowman co-hosted the hour-long swansong alongside Jimmy Savile who had presented the very first show.
The standard practice of wiping videotapes meant that most episodes prior to 1976 are considered lost media including any official recording of the Beatles' only live appearance. Only about twenty complete recordings survive from the first five hundred episodes spanning 1964 to 1973 with the earliest surviving footage dating from the 26th of February 1964.