After putting together broadcast logs for several NBC movie nights broadcast during the early 1960s, I realized that there might be some confusion over when each movie night aired. I've put together the following rough summary as a guide but do keep in mind that it is based solely on official fall schedules and thus doesn't reflect any last minute changes and only a handful of mid-season shifts. I've also opted to stick with the basic NBC [Day] Night at the Movies title rather than try to determine what the network actually called each of its movie nights over the decades.
When NBC introduced The NBC Saturday Night at the Movies in September of 1961, network television would never be the same. That's only slightly an exaggeration. Movie nights soon began popping up all over the place on all three networks. NBC introduced its own second movie night on Monday evenings in February of 1961. The Monday Night at the Movies returned for the 1963-1964 season, then, for the 1964-1965 season, the network moved its second movie night to Wednesday and The NBC Wednesday Night at the Movies was born. It, in turn, became the The NBC Tuesday Night at the Movies for the 1965-1966 season.
Things remained stable until the 1968-1969 season when NBC introduced a third movie night by bringing back The NBC Monday Night at the Movies. The NBC Tuesday Night at the Movies ended after the 1970-1971 season and NBC was back to just two movie nights. The NBC Saturday Night at the Movies ran through the 1977-1978 season and NBC shifted its original movie night by reviving The NBC Wednesday Night at the Movies for the 1978-1979 season.
Both The NBC Monday Night at the Movies and The NBC Tuesday Night at the Movies returned in September of 1979; The NBC Tuesday Night at the Movies would become The NBC Friday Night at the Movies in the spring of 1980. In September of 1980 The NBC Friday Night at the Movies became The NBC Thursday Night at the Movies. At that point, it seems as if NBC began moving its second movie night around every few months. At one point during the mid-1980s the network had three movie nights again before finally settling on Sunday and Monday.
The NBC Monday Night at the Movies went off the air following the 1996-1997 season, I believe, while The NBC Sunday Night at the Movies stayed around through the 2000-2001 season or so. If I've made any mistakes please note them in the comments. And if anyone knows of an authoritative account of NBC's movie nights be sure to let me know. My focus has always been on scripted network television programming so I haven't always paid much attention to movie nights, not even made-for-TV movies.