Minecraft can be measured into a quantity of aspects. For example, there is the "mining aspect", the survival aspect, and the building aspect. There are many more, some bigger, some smaller, but a big one that long-time players love is the "redstone aspect". The actual redstone dust comes from mining redstone ore. Despite it being called redstone dust, its physics resemble nothing other than wiring. When connecting it with a lever, for instance, the redstone will become active. You can use pistons to make doors, too. It can get quite confusing, and I find the best way to learn is through experience. It is actually quite similar to the Minecraft Pi API. There is only so much you can do, but you can combine different methods to make some pretty cool things.
A pretty popular and confusing mechanism that only extreme pros do, is making virtual computers. And not only that, they can even do simple things like calculating, and it's even possible to play virtual games! Whoever thought that Minecraft was simply survival and blocks? Here is one that I found interesting, which uses command blocks to make it easier. Of course, it was possible to make computers before command blocks were in the game, and those are the most complex. Here is an example. It's GIGANTIC! Three million cubic blocks?? Do you know how long that would take to build, even if you didn't have to stop every now and then to think about how it would work? It can do basic drawing, too. Of course, I'm not that advanced, but I do have my own share of complex redstone mechanisms. Here is a gallery of them:
I built it all on a server. It's a great server, and griefing is strictly illegal. If you want to join, the IP is clownercraft.net.