Have you involved Mother Goose or a cluster of Aesop's Fables yet? Really fun, oddball characters in those stories.
More than any specific story, I've had in mind a more devious concept for an isolated event or upcoming map, possibly involving magic or, even better, maybe some kind of "clean up and beautify the planet" idea. The premise is that certain items, like predator plants (which are very possible when transplanted to another part of the globe that has no defenses against them) will regrow at random intervals, so that places we've already cleared will have to be policed to chop down the nuisances again. Not so many of them that we'll get too frustrated and quit, just enough to drive us all a little bonkers, LOL ... and maybe the happy ending is retrieving enough of certain animals or plants from the first plants' native land to put an end to the ecological misfit (and then, of course, returning those also-foreign living things back to their homeland when the job is done). If ecology doesn't interest you, maybe tie it in with a Halloween event with the "zombie" plants being the result of a spell gone wrong. - You get the idea.
