The goddam "King In Black" event will still be going strong come March of next year, and it will still be generating new tie-ins (King In Black: Ghost Rider #1, King In Black: Scream #1, King In Black: Spider-Man #1 are all scheduled for March release). It seems like March will be the last month in which it's going on, though.
March is also when Marvel will begin celebrating the 50th anniversary of Man-Thing, Gerry Conway, Gray Morrow and company's 1971 Marvel Universe answer to The Heap. They will be doing so in a variety of ways, none of them as promising as the recent King-Size Conan comic celebrating that character's 50th anniversary (at Marvel), although I suppose it's still early, and they could publish a Giant-Size Man-Thing anthology or a month of True Believers reprints starring Manny.
First, they are doing weird-ass hero hybrid covers like Greg Land's variant for Amazing Spider-Man above, featuring "Spider-Man-Thing" (Ironically, that variant cover appears on an issue in which Spider-Man will debut a new costume; I think it's safe to assume it will not be that costume). Secondly, there's an Avengers series revolving around the character, which we'll discuss in a bit.
There are also apparently going to be "Women's History Month" variants, although I haven't seen any examples of them yet. I hope the latter are Alex Ross paintings of Susan B. Anthony fighting the Hulk or Elizabeth Cady Stanton swinging through New York City with J. Jonah Jameson tucked under her arm, but I suppose it will more likely just be pictures of Carol Danvers patting a little girl on the head.
Oh, and then there's this: