Battlestar Galactica: Razor
Between Seasons 3 & 4 the Battlestar Galactica movie "Razor" was aired. The movie can only take place between the 2nd Season episodes "Downloaded" & "Lay Down Your Burdens, Part 1". The movie features flashbacks that clearly demonstrate that "Razor" takes place shortly after "The Captain's Hand" - which is where most people seem to place the movie. But people that place "Razor" directly after "The Captain's Hand" are missing an important clue. During the episode "Downloaded" there are flashbacks to the original events of the miniseries which are dated as taking place 9 months ago. But in "Razor" there are also flashbacks to different events that took place during the miniseries which are dated as 10 months ago, meaning that "Razor" definitely takes place after "Downloaded". The survivor count at the start of the episodes also supports this order:
2x16 Sacrifice (49,590 Survivors)
2x17 The Captain's Hand (49,584 Survivors)
2x18 Downloaded (49,579 Survivors)
2x19 Razor (49,579 Survivors)
2x20 Lay Down Your Burdens, Part I (49,579 Survivors)
Some characters die during Razor, but it can be argued that some babies were also born during this time. Given all the clues, it seems clear that the writers intended "Razor" to be viewed (or at least take place) between "Downloaded" & "Lay Down Your Burdens, Part 1". And that's where I recommend that new viewers see the film. End of story.