You may be nominally aware that Marvel Comics is currently publishing a Big Comic Book Event (BCBE) wherein the Avengers (think Captain America, Iron Man) assiduously trade punches with the X-Men (Cyclops, Storm) with the clockwork regularity of a daily fiber supplemental. And like most BCBEs, the plot of this 12-part miniseries — which is helpfully titled Avengers Vs. X-Men — fans out over almost every other Marvel superhero comics like a Portuguese man o' war.
The mere existence of Avengers Vs. X-Men isn't surprising. BCBEs move a lot of glossy paper in an era when 97% of your average reader's attention span is devoted to photos of cat wearing bread slices as Renaissance hats. (Why do you think Watchmen is coming back?)