Not today, today, but 38 years ago in 1976 today.
Led Zeppelin appeared on American television for the first time to play Don Kirshner’s Rock Concert, a variety show that featured many big named acts. Led Zeppelin apparently avoided most television appearances because the sound quality suffered. A fair statement that was most likely true back then. Needless to say, there were some very lucky television viewers to witness such an occasion.
Read about how Led Zeppelin lost the first found in their court case and check out the Led Zeppelin Platinum Song Book.