"You can download it for free but the money one is better because it's got more stuff," says Ollie, excitedly, as he sits at the computer.
"You can get it on your iPod," adds Isaac, rolling his finger across the small screen.
A barrage of explanations ensues.
Ollie: "You choose your territory."
Isaac: "The aim of the game is to find resources."
Ollie: "Like stone digs faster, iron digs faster, gold digs faster."
Isaac: "You have a guy ... you just walk round and make stuff. Some people are really into it and they build castles and stuff."
Ollie: "When people get bored of it they watch videos of it ... it's kind of like real life except it's square blocks ... it's a good learning game, like maths, because you have to count the blocks ... Creepers blow you up and they can kill you ... it's like, what's going on? You don't know what's going to happen."
Lost?
Put simply, Minecraft is a game about breaking and placing blocks.
Lego-like in appearance, it is an open-ended game, without the violence of some other games. You use resources to survive and, although there are monsters that can kill you, if you die, you can "respawn".
You can play the game by yourself or with others on a server.
And, while the wild protestations by children when they are asked to give it a rest has many parents tearing their hair out, experts say it has educational properties.
"To me the premise of it is freeform play, which in a certain sense has a lot of educational value," says Allan Fowler, a senior lecturer in game design at Waiariki Institute of Technology.
"Children create their own environments and there is a lot of academic literature around that."
Mr Fowler has spent the last five years studying what children can learn from computer games, and their educational benefits.
As far as computer games go, Minecraft is one of the good guys, he says.
"I've seen it used to learn core programming concepts. Some other people use it for learning language.
They use the basic platform with learning aspects in there," he says.
Mr Fowler's own children, aged 4 and 8, play Minecraft.
"Most games my kids play have an educational content, which I think Minecraft does. It's not direct, or obvious. It's more subtle ... the learning process of making something," he says.
But, he is careful to limit their screen time to half an hour a day.
"Any tool can be used for good and any tool can be used for harm. I know kids that probably use it excessively. When anything is used to the detriment of other learning opportunities then it's not a good thing, whether it's Minecraft, playing with toys or reading books. It all needs to be in balance," he says.
"Letting kids play is really important, no matter what they play with."
Garry Falloon, associate professor of e-learning at the University of Waikato, also espouses Minecraft's benefits.
"It's a very interesting game because there's a lot of collaboration happening in it," he says.
Professor Falloon's teenage son has interacted with other players from all over the world and even met his girlfriend through playing the game.
"It's the international reach of the program. You can work collaboratively with people worldwide ... it's really, really powerful stuff," he says.
"Looking at it from a parent's point of view, my son's run his own server for two-and-a-half years. He has interacted with people from South Africa, France, Germany, the United States and Australia ... he's also finding out what's going on in their world, which is a side benefit, the global reach."
While technically quite primitive, playing the game involves "tremendous high order thinking", says Professor Falloon.
"There is a lot of economic, social and environmental learning that happens with it," he says.
"It allows you to apply these concepts in a virtual world. The big thing is bringing these learnings into the real world ... then it becomes productive knowledge."
There are educational versions available and he would like to see it used more in schools.
"It's certainly a potentially very useful educational resource."
While some may worry about the "addictive" nature of Minecraft, Professor Falloon says it all depends on how it's used.
"You don't want it to become a babysitter," he says.
"The biggest problem is monitoring the time kids spend on it.
That's an issue with technology per se.
I dealt with it by putting a timer on the router.
"But it's certainly better than a lot of them [computer games]. I would much prefer my son to play Minecraft than 99 per cent of the games out there."
Ollie and Isaac's mother, Tania, also subscribes to this.
The boys are given 30 minutes to an hour a day to play a computer game or watch television.
"They get set times and that's pretty much it, otherwise they would just keep going and going," she says.
Mrs Hilliam says she got her husband, Paul, to check out the game first to make sure it was appropriate.
"He's played it and he said it's a pretty good game and there is nothing wrong with it. It's quite creative and not violent," she says.
When the "Zombies" and "Creepers" come out the boys go "hyper and crazy" and when there is a group of them playing together and traversing each others' worlds it reaches fever pitch.
After a particularly heated game she sends them outside to let off steam.
"They get loud and excited but a game of hide and seek can cause the same excitement. It's the adrenalin," she says.
But, like many parents, much of it still remains a mystery to her.
"It's just blocks everywhere."