Sorry to have such a long break in postings; it's been a heck of a year.
The story of Sodom and the Cities of the Plain in chapter 19 of Genesis is one of the most infamous in the Hebrew Scriptures, mostly because of its association in modern debates about homosexuality. Frankly, though this is a popular reading of the text, it is a misreading. The only way to make this a story about homosexuality is to start with the conclusion then use convoluted logic to try to justify yourself.
As with any text, the best thing to do is to strip away any preconceived ideas you have about the story before reading it with a clear mind. Here is the story in the New Revised Standard Version of the Bible and here it is in The Message paraphrase version.
The story opens as a pair of mysterious wanderers enters the city of Sodom. In the last chapter there were three of them, and when Abraham spoke to them, the text says he was speaking to the Lord. There isn't any explanation in the text about why there are now two men instead of three. A traditional explanation is that the three were God in human form with two angels, but the story itself doesn't offer any such explanation. While it irritates us modern people not to have a simple, logical answer, it's good to remember that any explanation like this we come up with is out own invention and not really a part of the story.
The travelers are now identified as "angels." The Hebrew word is malakim and literally means "messengers." There's nothing here to suggest these guys fit our traditional image of wings, white robes and a halo. As far we can tell, they look like anyone else and it doesn't seem to be the case that Lot (or anyone else in the city) suspects their true nature.
As I mentioned in chapter 18, the peoples we're dealing with in Genesis shared a tradition of hospitality. When a stranger showed up, you were supposed to offer them hospitality and protection. This was a matter of kindness but--even more important to the people of the time--it was a matter of honor (reputation). To give a guest lavish hospitality was to establish a reputation as a wealthy and generous person, which gave you a lot of standing in the community. To fail to do so was to gain the dishonorable reputation of being poor or stingy.
The angels say they are fine with sleeping in the plaza, but Lot insists. He might be doing this because he knows the plaza in Sodom isn't a safe place for strangers or he might be doing it because entertaining strangers is a good way to build up an honorable reputation. He could even be doing it from a mixture of motives. It's impossible to say for sure. In any case, the angels accept his offer and become his guests.
Then bad things begin to happen. The men and youths of the city learn that Lot is entertaining two strangers. They show up at his door, demanding that he send the strangers out. The men want to "know" them, and in the context it's pretty clear this means they want to gang rape them.
Let's stop there for a moment because this is the point where a lot of commentators claim the story is "obviously" about homosexuality. If a group of men wants to rape other men, they have to be gay, right?
Actually, that's pretty clearly not the case. If you look at gang rapes of men by men you find that most of the rapists are heterosexuals. Studies of the psychology of gang rape show that it's a crime of violence rather than of sexual desire. It's also a mob mentality sort of crime. Most of the perpetrators in a gang rape would normally never consider raping anyone but, caught up in the excitement, camaraderie and anonymity of the mob do it anyway.
The target of a gang rape isn't someone the mob members would normally want to have sex with either; it's just a convenient victim. In this case, the strangers were likely chosen because they had no social connections in the city and wouldn't be staying there. In other words, there weren't going to be any consequences from this crime. It's very similar to the story of the rape of the Levite's concubine in Judges 19 where the victim was a woman. In neither case did sexual orientation have anything to do with it; the mob just wanted a victim.
Lot decides he needs to protect his guests. This might be his compassion at work, but it's more likely his sense of honor. The obligation of a host is to protect his guests because doing so gives you the honorable reputation as a strong and brave man. Failing to do so gives you the reputation of being weak and cowardly. In a culture like this, where an honorable reputation is everything, people are willing to make terrible sacrifices to keep their honor intact.
That's probably why Lot (who has got to be one of the all-time worst fathers) does what he does next and offers his two virgin daughters to the crowd. He surely doesn't want to see his daughters gang raped and possibly killed but, in his culture, it was preferable to seeing his honorable reputation ruined. This is the same sort of honor-based thinking that led to fighting duels over insults and still leads to honor killings in many parts of the world. (As you can probably guess, I don't think this is a good thing, in Lot's age or ours.)
The mob insists on its chosen victims but the angels have their own card to play. They cause the men in the mob to go blind. This seems like poetic justice because the men were already blind in a sense. They were blind to the nature of the strangers, blind to the consequences of their actions, and pretty much blind to everything except for the excitement of being part of a mob.
There's an odd scene after the angels rescue Lot and his wife and daughters. They tell him to head for the hills but he doesn't like that plan and bargains with them to spare a small city (Zoar) so he can go there. (Arguing/bargaining with God is really a lot more common in the Hebrew Scriptures than we often assume.) The angels relent (winning arguments/bargaining sessions with God is also more common in the Hebrew Scriptures that we imagine) and spare the town.
Lot tries to persuade his daughters' fiancés to come with them but (as in the story of Noah) the people you try to rescue often don't listen. He runs with his family to Zoar as the cities are destroyed. His wife looks back and gets turned into salt. Then Lot hides out in the hills where his daughters get him drunk and seduce him (ick!) It's a pretty dramatic ending and leaves us with a lot of unanswered questions. Some of which are:
1) What made the cities so bad that God felt the need to destroy them?
Genesis tells us that they were really, really bad, though the writers don't feel it's necessary to be any more specific than this. Sodom is mentioned in a number of other places in the Bible, and they all say the people there were bad, but don't get specific either. The two exceptions are Ezekiel 16:46--which says it was social and economic injustice--and Jude 1:7 which says it was sexual immorality. You can see both ideas having some validity in a town that thinks it's okay to gang-rape or otherwise victimize helpless people like strangers. But the problem is pretty clearly the dehumanization and exploitation of others, not sexual orientation.
2) What's the deal with the fire and brimstone? And what's up with the pillar of salt?
I remember my 6th grade science teacher (who was a big Von Daniken http://en.wikipedia.org/wiki/Erich_von_D%C3%A4niken fan) explaining to us this was clearly a reference to an atomic bomb, which must have been created by aliens from another world. I've heard others say that this must clearly be lightning, or meteors, or a volcano, or the supernatural power of God. Since there's no evidence that this story is in any way historical, I think it's just a picturesque way of talking about God's power and not meant to be taken too literally. Same thing with Lot's wife. The message seems to be "when God tells you not to look back, don’t look back." It may be that there was a pillar of salt out in the desert and the story was used to explain its presence, but this is another example of a tale from the Hebrew Scriptures that falls apart when you try to be too literal about it.
3) Doesn't this story make God out to be a ruthless mass-murderer?
The story of Sodom is like the story of Noah. Both show God as violent and judgmental, which might be a little easier to take if we had a better idea of what the "wicked great sinners" had done to deserve it. They are both ancient stories and reflect a primitive understanding of God which is gradually overshadowed by a more sophisticated view that focuses on God's compassion.
4) What's the point of the incest between Lot and his daughters?
It's probably added to the story as a taunt. The Israelites had a lot of problems with the Moabites and the Ammonites. They lived in the same territory and were often bloody enemies. Even when they were getting along, there was a lot of tension. This detail was probably made up as a way to insult the Moabites and Ammonites by saying it was an act of drunken incest that gave rise to their cultures.
5) What's the moral lesson here?
There's not always one in Bible stories, and there really isn't any kind of role model here. Even God doesn't come off very well in this story. The only lesson I see is: Don't victimize others like the people of Sodom did. When people are treated as objects to be abused or ignored, God doesn't like that.