The Borg on Enterprise.
For a series set two hundred years before the TNG era, Enterprise at times dipped into the familiar-alien well prematurely. The Borg are amongst those aliens cited by many fans as not belonging on the show. But the events of First Contact presented the writers with a unique opportunity not only to bring these popular cybernetic villains onto the show, but to create both a sequel and a prequel to the wildly popular Next Generation film.
In this episode of Warp Five, Christopher Jones and Tyler Johnson are joined by Earl Grey's Darren Moser to discuss the Borg's appearance on Enterprise, whether Picard should have cleaned up after himself in the Arctic so Archer wouldn't have to, why Starfleet has no record of the Borg in "Q Who," and whether or not this all takes place in an alternate timeline.