It kind of does make a great story, though, doesn't it? I always liked this one best in terms of drama. It has a big budget premise and an interesting protagonist. The film versions all treat it like a fairytale, which is boring — it should be done realistically. Noah is the patriarch of a rich, influential family in a region that has been rattled by a string of ominous events: Animals behave strangely, the earth shakes (as opposed to the characters, the audience can explain these small earthquakes rationally), rumors of a faraway, fiery mountain make the rounds (a volcano has erupted someplace else), the sky darkens slightly (due to the dust from the volcano). Harvests fail. The people are afraid, among them Noah — who has what today might be termed schizophrenia. He goes to the mountains to converse with God (the voices in his head), to ask him for mercy. During one of these retreats Noah finds an object that he interprets as God's way to warn him of the imminent catastophe: A shell. Again, the audience is aware that prehistoric shells can be found nearly everywhere in the world, because almost everywhere was the bottom of the sea at one time or another. To Noah, the shell is a sign that God intends to punish his creation with a great flood. Noah's voices start telling him to build the ark. No one around Noah has a way of knowing what schizophrenia is, and he is powerful and rich. Empowered by the force of his mania, he overcomes all obstacles and succeeds in building the ark — which is large, but nowhere near as large as the absurd wooden tanker of the collective imagination. And when Noah collects a pair of every animal in the world, it's not the world as we know it, of course, but as he knows it, which would dramatically reduce the number of animals the ark would have to be able to carry. Noah might even (sensibly) restrict himself to animals that would in some form be useful for human survival after the flood. Camels, donkeys, cattle, cats, dogs, horses, goats, chicken — that's about it. Noah has ruined his family's wealth, reputation and position of power in the process of building the ark; then the flood hits. It's not rainfall that causes it, of course, but a tsunami, caused by the massive earthquake that has been foreshadowed by the smaller quakes and the eruption of the volcano. The ark is swept out to the open sea, so that Noah believes that his premonitions came to pass — he, his family and the animals on the ark appear to be the last surviving creatures in the world.

Tl;dr: Noah's Ark needs a gritty reboot.