Sci Fi Wire reports that Carnivale is gone:

HBO confirmed that it is canceling Carnivale, its Depression-era supernatural drama, after two seasons, Variety reported. HBO had produced a total of 24 episodes in the show's run.

It was a pretty decent show - I liked it well enough, my wife loved it. I wish they had just ended it instead of giving it the ambiguous send off they did. Compare the ending of the show (where the Preacher was being brought back by Sofie) with the way "Buffy" always wrapped a season, or with the way "Veronica Mars" ended last night. In both cases, a season wrap could stand as a series wrap if the show bit the dust.