I was thinking about this today. 'The Menagerie' was supremely clever for its use of the original pilot footage, given that said pilot episode was effectively unbroadcastable by the time Star Trek made it to air (the format and cast had changed too much). But I was thinking: has there ever been another TV show which did anything similar? Or was it a true stroke of genius on Gene Roddenberry's part, this idea that maybe the footage of Pilot #1 could be salvaged somehow (let alone allowing the broadcast of practically the whole pilot episode)? It just struck me that it seems to be a pretty unique thing. I mean, television is full of examples of pilot programs where the cast is different and therefore the pilot can't be fit into the series' continuity (sometimes those pilots end up being reshot with the new actors). I suppose the true piece of luck in Roddenberry's case was that Leonard Nimoy managed to survive all the way through to the series proper, so as giving an excuse to revisit the events of 'The Cage'.