Minecraft - Los Angeles,CA

It is essentially digital Legos. They build and destroy. It's not violent, it's oddly popular, and I will say my kids have made some amazingly creative things with it. I was really on the fence with it but I have to say they do actually use their brains.

*ETA:
Creepers: http://minecraft.wikia.com/wiki/Creeper

Minecraft, is like giant pixels. Pixel blocks. That is what it is. Pixels.
And the kid/adult, can create anything in it. Using the pixel blocks.
Some Minecraft players, adults... even create replicas of things like the great Egyptian pyramids, hotels, architecture etc.
It is for children OR adults.

My family, we play it.
It is a very... creative, and intelligent "game", and uses problem solving and thinking outside the box.
My son who is 7, astonishes me with what he creates... very complex scenarios. He creates creatures... and creates all sorts of habitats for them and for him, and trails and up in the sky and on earth, and has things for his creatures to do.... such as if they go on a certain path, and trip a torch lever, they can then open a door etc. My son likes creating scenarios....with it. It amazes me, his thinking process. Some like creating objects, or replicas of the 7 wonders of the world or things, etc.
Anything goes. There is no "rules."
A prestigious private school in my State, even has a Minecraft club, and their own server.... and they do all sorts of things, in it. It is a learning.... venture.
It also teaches computer gaming/programming. Which my Husband teaches our kids.

It is not violent.
It is not gross.
It is not inappropriate.
It simply utilizes giant pixel "blocks" to create anything the user wants to.
And it is not just a "dumb" video" game.

In our house, we can play it on the Xbox or iPad or on the computer. It is different on each one. And many times, my Husband, daughter and son, all play together, and play games or build things together.

There is "creative mode" and "survival" mode on it.
In survival mode, you need to have things in order to survive. ie: trees for wood to cook, pigs to use for meat, fire, etc.
And in creative mode you just do anything you want.
The "music" or sound on the game is very peaceful. NOT all hyper or aggressive at all.

Some people do not like it. Because, it is not a literal... type of "game." The user... has to come up with things themselves. To do in it.
My son even tried teaching his Aunty and Grandma how to play it. It was too wide open for them. Meaning, they would just rather play a game that was blatantly telling you, what to do.

The possibilities with Minecraft, are endless.

Veruca Salt has it nailed.

You can create ANYTHING on Minecraft, and yes, it is basically digital legos. My kids like to build houses and rollercoasters and collect cats and dogs as pets. Some people will create amazing things like models of the Starship Enterprise or the Hunger Games or even their own neighorhood.

There are monsters that can come destroy you on "survival mode" but it's really tame. I let my 5 year old play it.

The only bad thing about it is the kids get obsessed and talk about it constantly. So you will have to deal with that, ha ha.

My daughter loves it. I have seen nothing wrong with it.

My 6 year old loves it. It's innocent just building stuff.

There are settings for no fighting (my son calls it "peaceful mode"). My 9 yo loves this game.

I would also suggest Build with Chrome. It is Lego. You build in a 3 D world using Lego bricks. Click size, color, place it and build what you want. Need to create a Google account to save your creations. There are no creepers or anything like that as of yet. It is fairly new I believe and my 10 year old is preferring it to Minecraft at the moment. But he is a Lego fanatic.

The kids and my husband play. I hear him yelling from one room to the other for someone to shut the door they left open, he's getting zombies. He downloaded it on their devices and he plays too. It's fun and everyone loves it. Kids are 7 and 10 but they've been playing it for over a year. At 5 and 8.

My boys (6 and 8) play and they love it. They are so creative, they tell me how they have used different things to make the houses, forts, pools, whatever. I think it's a good game, but like anything, not something they should do all day every day.

It's fine. I don't play but I've watched a friend's kids play. Nothing in it that would bother me.

My 7 year old loves it. Think of a big online lego set. He builds houses, amusement parks, etc.

Updated

My 7 year old loves it. Think of a big online lego set. He builds houses, amusement parks, etc.

Ditto Veruca.
Kids love it
Many blessings