Some beautiful words have already been written here, here, here, here, and here. The Church's YouTube channel, Mormon Messages, has some beautiful videos with better explanations that I could ever give.
So, I'm not going to address the purpose of temples, as that is covered. I will, however, address some responses I've seen from those explanations.
When my co-workers asked me about the uproar about the HBO show, I explained the Church's statement, and then likened it to other sacred religious ceremonies. I then said, "It's as if someone took what was most sacred to you and put it on national television for all to see."
The response was unanimous - "I wonder what that would be." Not knowing for them, I shrugged, and the conversation moved onto something else. Eventually I felt sad for them, not because they aren't members of my church or something, but because they didn't have something they could readily think of as being sacred.
If you look up the word "sacred", it is usually used to describe something of a religious nature, but it can also be used to describe something "worthy of respect or dedication" and can be ascribed to anything - people, objects, times, or places.
So, what can be sacred to you? Your relationships? Your home? Your wedding day? A talent you have? Whatever it is, there's bound to be something, and having something, anything, that is sacred to you is actually very important. From one of the articles I referenced above:
When nothing is sacred, everything is fair game in conflicts of ideas, attitudes, or behaviors. If something is sacred, then some ground rules of harmonious interaction are possible.
I believe that. In other words, stand for something, or you'll fall for anything.
Secondly, in some comments I read on other blogs, some people voiced concern that no one is taught, in missionary discussions or even growing up in the Church, exactly what takes place in the temple. They argued that because it might seem somewhat strange to most, people would benefit from more instruction before they go for the first time.
While I didn't know entirely what to expect during my first temple visit and it's definitely different from the things that take place in most other Church meetings, the principles there are the same - eternal progression. We're told that we will learn the gospel, and everything else we learn, "line upon line, precept upon precept". There's no way that we could learn everything about anything right way. Even learning how to walk and talk as children takes more than one try and a lot of time and effort. Mastering something, from cooking a meal to learning a new language, takes time, and lots of it.
So, what we learn and do in the temple is just another ordinance and precept necessary for our progression. We can't even begin to understand it, or anything else, before we're ready and willing. We wouldn't start running before we learn to walk, and we won't understand a new language unless we really want to. That's also why we attend Church every week and read our scriptures daily, and otherwise practice our religion constantly, so that we may continue to grow and improve. I've been a member all my life and there are still things I need to learn and perfect. Unlike other denominations, just saying "I believe in the saving power of Jesus Christ" will not secure me a place in heaven, I have to act on that belief, and attending the temple is just another part of that.
I love the temple. I love the opportunity to learn and grow and serve, but I also enjoy the respite, peace, and protection from the world and feeling closer to Heavenly Father. I don't expect everyone to understand or believe the same way, but as long as they respect my beliefs, I'll respect theirs.