I normally don't get into these big comic book events, but this one has been building for decades now. In short, the Phoenix force is returning to Earth. The Avengers want to stop it (or at least divert it), but the X-Men want to control it to help restart the mutant species (which was almost completely wiped out by Scarlet Witch in "House of M"). That's where the clash between teams starts. They are about 9 issues in (out of 12) and I don't really see how things can go back to the way they were at this point. Too much damage has been done on both sides.
This series is going to lead into the Marvel Universe "relaunch" called Marvel NOW! (the exclamation point is theirs not mine), which will see more of a blending of the Avengers and X-men teams and not have them, for all intents and purposes, inhabiting almost completely separate universes like they are now.
The most exciting news (at least for me), is that they will be bringing back the original X-Men team from the 60s! (Okay, that time the exclamation point was mine.) In what is sure to be a major abuse of the space-time continuum, Cyclops, Marvel Girl, Beast, Angel and Iceman, from Stan Lee and Jack Kirby's original run on the series, are going to be transported into their future, our present, and decide that the current Marvel Universe is waaaay too screwed up for them to go back to their proper timeline. Which means that there will be two versions of Cyclops, Beast, Iceman and Angel (assuming all 4 of those guys survive AvX - at least one major character isn't making it out of AvX alive) walking around.
I'm still a bit miffed at Jim Lee for breaking up the O5 (original 5 X-Men) back in 1991 and then bailing for Image Comics. I've been waiting over 20 years for them to be reunited in the mainline Marvel Universe (not some kind of weird alternate reality like Children of the Atom, First Class or Season One). So human Beast and pre-Phoenix Jean Grey will be mixed back into the Marvel continuity. This is huge news for me. HUGE!
Just to put my excitement level in perspective, for me this right up there with the announcement of the Prequels in 1995.
So, yeah, anyone else reading AvX?