There are two schools of thought on The Brady Bunch, which anchored ABC's Friday night lineup for 5 seasons (1969-74), and became a cottage industry in and of itself. One side of the argument was that it was a breezy, family-friendly sitcom that became a cult favorite, leading to it being revived in a pair of feature films. The other is that it is considered by some as one of the worst sitcoms of all time, for no other reason than the facts already stated, and that certain of later generations just don't understand its appeal.
During season 3, Greg, Marcia, Jan, Peter, Bobby, & Cindy (Barry Williams, Maureen McCormick, Eve Plumb, Christopher Knight, Mike Lookinland, & Susan Olsen) formed a vocal group to help raise some money. One of the songs used in that episode, "It's a Sunshine Day", became an instant classic, and somehow, someone at ABC convinced creator-producer Sherwood Schwartz (ex-Gilligan's Island) that it might be a good idea to spin the kids off into their own series.
The Brady Kids, then, was licensed out to Filmation, which co-produced the series with Schwartz's Redwood Productions & Paramount, and debuted in September 1972, and holds the distinction of launching a second series the same day. That is to say, the first episode of Brady Kids was also the first installment of the ABC Saturday Superstar Movie, and would later be rebroadcast as a 2-part Brady Kids episode later in the season. As a result, viewers got 90 minutes worth of Brady in one day, which at the time was unprecedented.
After the first season, half the cast left in a dispute over money (what else?), forcing producer Lou Scheimer to have two of his kids, Erica & Lane, fill in, though the musical numbers were held over from the previous season. Not surprisingly, the series was cancelled after 2 seasons, and Schwartz & Filmation replaced the Brady Kids with The New Adventures of Gilligan.
Perhaps the most notable thing in the series' brief history was that it helped build the foundation for ABC's keystone toon franchise of the 70's & 80's, the Super Friends, as Superman & Wonder Woman guest-starred in separate episodes. The Superman episode, "Cindy's Super Friend", isn't available on YouTube, however, and the fact that the use of the two Justice Leaguers, whose rights---of course--belong to WB, coupled with CBS-Paramount's lack of interest in releasing the series on DVD, may preclude it from ever seeing the light of day again, even with the series marking its 40th anniversary this year.
The real highlight of the series was the musical numbers, usually introduced by Marlin, a mynah bird/sorcerer (Larry Storch, ex-F-Troop), and run at the end of each episode, a la Fat Albert & the Cosby Kids, which also launched in 1972, and was a more successful series. Windsorbear uploaded "I Believe In You", and it sounds like Maureen McCormick is on lead vocals....
Tres cheesy, no?