In an episode when Homer's party caused a lot of rain and flood and all of that, Ned thought it was god bringing down the great flood again to wipe out the wicked. He built an ark and had 2 animal of each kind on it, but no females, though. He didn't want indecent acts on his boat.
I know the whole thing was suppose to be humorous, but this reflected a very important part of christianity. The reason Noah had 2 of each kind of animal on his ark was to repopulate the earth. All Ned was worried about was the 2 of each kind on his ark. Never mind the repopulation thing. He did this simply to make himself some kind of saviour but deep down inside he didn't really care about the purpose of his action.