We already previewed the first few pages of Avengers vs. X-Men #1 this morning and now we've got an exclusive reveal of one of the grudge matches that'll be coming out of that miniseries.
Interestingly, Prince Namor -- aka the Sub-Mariner -- is currently an X-Man but has been an Avenger, too. And while most people know Ben Grimm as the Fantastic Four's resident strong guy, he's an Avenger, too. These two have battled before back when Namor was more villain than hero. The AvX event starts in April; here's Marvel's description of this tie-in issue:
UNCANNY X-MEN #12 KIERON GILLEN (w) • GREG LAND (A/C) • AVX TIE-IN! • The Avengers and X-Men take their battles world-wide. • Return to Tabula Rasa!