When it comes to either something in-universe (concerning characters, stories etc.) or real-world stuff involving creators...what are some things about the X-men that you feel more casual fans, general audiences, or even some hardcore fans might not really be aware of.
I think a big part of early X-men history which most people would be surprised to hear about is that the X-men basically started out as a covert division of the FBI! Xavier collaborated with an FBI Agent named Fred Duncan and he was the one who gave the team many of their mission to take down ''evil mutants''. Fred Duncan showed up on and off during the original 60's X-men run, at one point even disbanding the team after Xavier was presumed dead. The much-later mini-series
Children of the Atom elaborates on Duncan's key role in helping Xavier set up the school and find the mutants who would become the original X-men.
To its credit,
X-men First Class does pay homage to this largely forgotten aspect of X-men lore. The 'Man in Black' character is basically a stand-in for Agent Duncan, and the X-men start out as a division of the CIA rather than the FBI. And people say that the Fox movies were not ''faithful to the comics''
Its kinda surprising this hasn't come up very often since it does have some interesting implications in-universe (and out) about the X-men's mission and Xavier's dream. I mean, if you want to apply the civil right metaphor literally to the X-men (which I usually don't, but it is undoubtedly a popular reading of the franchise) this would be the equivalent of a black activist group in the 60's working as covert assets of the FBI to help them capture black militants. How you feel about it depends on your politics, but its definitely something that has political implications when seen through that prism.