A thread in the DS9 forum about Picard and Sisko got me thinking about this. There's plenty of crossover references where an episode (or film) will reference something that happened elsewhere. TNG referenced TOS: Naked Time/Naked Now, Riker's mention of passing by Camus II in TNG's 80th episode - a way of acknowledging that TNG now passed TOS in number of episodes produced DS9 referenced TNG - O'Brien (and sometimes Worf) talks about how different things are compared to the Enterprise. DS9 referenced TOS - Trials & Tribbleations, the various Mirror Universe episodes. VOY referenced TOS - When Harry and Tom were trying to make a new EMH, one of the medical databases they had to upload was something written by Dr. Leonard McCoy. VOY referenced TNG and ST:FC - B'Elana mentions Data, Seven mentions the Phoenix and ENT is full of "reverse" references. So given all that... What are some missed opportunities for crossover references they could have done? Doesn't have to have been a whole episode - could just be something as simple as a one or two minute scene, a visual clue or even a couple of lines of dialogue. One I always thought would have been cool was a simple way they could have tied the Borg battle in ST:FC into DS9. Take one of the DS9 episodes from somewhere in that season when FC came out in theaters - one where Worf wasn't needed for the story - and have Sisko receiving orders from Starfleet to send him off with the Defiant to fight a sudden Borg attack on Earth. Somewhere near the end of the episode, or maybe in the following episode, have Worf return and a quick dialogue exchange between him and O'Brien mentioning that the Defiant needs a lot of repairs. So, what kind of references would you have thrown in to an episode or movie here and there? And just to keep this a little more focused - I'm not interested in possible character cameos. That's a whole separate discussion that's been had plenty of times around here.