Continuity mistake: In this episode, Lucy goes out on the window ledge. In "Lucy Cries Wolf", the window ledge was very different: the walls were made of dark brick instead of concrete blocks, there was no downspout, and the ledge went into the corner and stopped, no continuation on the other wall.
Continuity mistake: In the scene where Superman comes to Little Ricky's party Little Ricky has on a birthday hat. When Superman picks him up the hat is gone; it reappears when Superman gets ready to leave.
Revealing mistake: While Lucy is out on the ledge, if you look at the pipe as it runs from above the ledge to below it, the two pieces of pipe don't line up. They are off about the full diameter of the pipe. Also when the pipe pulls out, it's obvious the pipe is on a hinge at the bottom and not really attached to the lower pipe. Later, there is also no stream of water falling from above where the pipe was supposed to be connected as a drain even though it is pouring out.
Answer: According to Snopes.com, there is no definitive answer, but the mid-1960s is the most verifiable date with "The Munsters" being cited as the first, although others claim "The Brady Bunch" showed the first couple seen in a double bed. An early TV show from the late 1940s titled, "Mary Kay and Johnny" is also thought to have shown the married couple's bedroom as having a double bed, although probably not with them in it. However, this was when TV was aired live, and there are no surviving episodes, only anecdotal accounts.
raywest ★
Something that is funny is that in the movie "A Christmas Story," they show the parents having two twin beds in their bedroom. In a real situation, they should have shown them having a double bed. Lucy and Ricky had twin beds pushed together in an early episode, which would have been pushing television boundaries in that time.