It was recently announced the X-Men: First Class sequel would officially be called X-Men: Days of Future Past. The title comes from a 1981 storyline that went from the present and the an alternate future where the Sentinels rule the United States and mutants live in internment camps. The X-Men animated series from the 90′s took a page from the arc when Bishop was sent back in the future to 
change history. Details on the film are being kept under wraps (it is being written now), but any potential variation on the comic storyline could make for a great film. Here is a full summary of the comic arc via Wikipedia . . .
The storyline alternates between present day, in which the X-Men fight Mystique’s Brotherhood of Evil Mutants, and a future timeline caused by the X-Men’s failure to prevent the Brotherhood from assassinating Senator Robert Kelly. In this future universe, Sentinels rule the United States, and mutants live in internment camps. The present-day X-Men are forewarned of the possible future by a future version of their teammate Kitty Pryde, whose mind traveled back in time and possessed her younger self to warn the X-Men. She succeeds in her mission and returns to the future, but despite her success, the future timeline still exists as an alternative timeline rather than as the actual future. (The Official Handbook to the Marvel Universe: Alternate Universes 2005 gave the numerical designation of “Days of Future Past” Earth as Earth-811).
Aftermath
Rachel Summers, who was a key player in the original storyline, traveled through time from this alternative future, Earth-811, to the present day and joined the X-Men. Nimrod, the “ultimate Sentinel”, followed her to the present and became a foe of the X-Men and the Hellfire Club. Another supervillain, Ahab, later followed her to the present in the Days of Future Present crossover.
Days of Future Present
Ahab kidnapped the children Franklin Richards (son of Mister Fantastic and the Invisible Woman and, in the future timeline, Rachel’s love) and Nathan Summers (son of Cyclops and Madelyne Pryor) but was defeated by the X-Men, X-Factor, the New Mutants and the Fantastic Four.
Meanwhile, Rachel joined the European mutant team Excalibur, whose series twice revisited the “Days of Future Past” timeline. The first time was in a story by Alan Davis entitled “Days Of Future Yet To Come,” in which a time-traveling Excalibur and several Marvel UK heroes overthrow the Sentinel rulers of future America. This storyline also revealed that Excalibur’s robotic “mascot” Widget had been possessed by the spirit of the future Kitty Pryde.
A similar but distinct reality[3] was seen in a vision by her teammate Captain Britain. This story, “Days of Future Tense,” revealed the final fate of that timeline’s Excalibur team.
A prelude to Days of Future Past was produced in a three-part mini-series entitled “Wolverine: Days Of Future Past.” This three-issue mini dealt with ramifications between the catalyst for the creation of the alternative future up until the main storyline in Uncanny X-Men 141-142. The prelude explains why Logan leaves for Canada and why Magneto is in a wheelchair in the main two issue story.
Another view of this reality was presented in the second issue of Hulk: Broken Worlds. A short story, “Out of Time,” examines the life of Bruce Banner (the Hulk) in a Sentinel prison camp.
Here is what Bryan Singer recently told IGN about the sequel: “I can say that it’s being written right now and it will start shooting in a few months. It’s going to be very ambitious; it’s called Days of Future Past and it deals with aspects of that comic, but also some very new things. I don’t want to give any of it away. Matthew Vaughn will be directing and I’m totally excited about it.”
“I think there’s a strong desire to broaden out the universe. I mean, the X-Men universe is every bit on its own as big as the Marvel universe. I think it’s time to reach out and explore it and perhaps even bring some connectivity between the films as Marvel has done so well. You may seem some of that.”
Sources :
Wikipedia
IGN
