I've actually seen the Giant's Causeway in person, alongside some folks from North Britain somewhere that only spoke English-english.
You've got an impression of the causeway from these blogs, but you really don't get the real feel. So before you lot start thinking about game design, let me tell you what it's like to be there.
First off, it's cold, because this is the northern tip of Ireland and it gets all the bad weather. Plus, it's right up against the ocean. Obviously.
Now, these hexagonal stones are actually hexagonal pillars all crammed up against each other, and they rise and fall like everything else in Ireland: a lot. In the popular spot you've got a few wobbly plains of these things rounded and interrupted by steep little hillocks you can only climb if you ignore the "don't climb" signs and put your back into it. Since it's on the seashore, the stones are often wet, making climbing them even more entertaining.
However, simply wandering around getting to see hexagonal pillars isn't all there is to do in the giant's causeway. There are a lot of other formations in the area, and it's a great place to go birding because it, like all of north Ireland, is infested with titanic cliffs. The view from on top of the cliffs is incredible as well, which I can tell you not because of my amazing cliff-climbing capabilities but because there is a nice path up to the top.
The path crosses in front of a few other kinds of weird freaking formations, including "pipes" running like support beams from the bottom of the cliff to the top. It looks like the whole of the cliffs is a supersized church organ that got partly buried over a few thousand years of disuse.
The area is very interesting, but what struck me about it was less the rubbish touristy stuff and more the fact that all of these rock formations were formed with the same mechanic. And if you look into it, there's hexagons everywhere: when you boil water, it boils in hexagons, for example. I, being a science geek, was amazed.
Personally, I'd prefer to make games out of some of the other Irish tourist attractions, such as pubs. I mean, such as the dozens of older-than-stonehenge-and-still-standing stone age structures such as Newgrange and surrounding areas. Thousands of years old and still waterproof. I'd love to play around with a building game that's more about how LONG your structure will last rather than getting it to fire a ball through a hoop or light a rocket or whatever.
Or how about the inland tidal ponds that completely dry up at low tide? Or, and here's an amazing new idea, castles!
Anyway, just keep in mind that the physical presence of the Giant's Causeway is more impressive than the text you've been reading. If you do think of a game based on it, make it a game that takes into account the actual setting, not some imaginary, boringly idealized setting.