When I first stumbled upon Sky Nations about 6 months ago I dismissed it as just another Minecraft clone, but it is a lot more than that. The game is still a bit buggy and unpolished, but it is getting better every day. For a single-developer game the progress is impressive.
Anyway, as is probably clear from the images and descriptions, you build airships and fly them around collecting resources to build more things. You start out with a humble twin-engine platform and over time it can be expanded in any way you want. You can add additional engines and install cannons to fight other players, as well as add more floors and stuff like that to the ship. I'm poor at explaining things but that is the gist of it. There is also a hat creator but I haven't delved into that much. It looks interesting.
The community has always been nice and helpful and the dev responds to support requests quickly. Like any game, Sky Nations has its flaws, but I am confident the dev will keep improving it. One such issue is that all the official servers seem to be hosted in the UK. Hard to blame the dev considering that's where he lives, but it would be nice to have a NA server as well. My ping is always 150+ and there isn't anything I can do about it unfortunately. That being said, I highly recommend anyone with an interest in steampunk stuff who enjoys games like Minecraft to try this game out.