I don't know, aren't they making nanobots or some shit that will be able to do complex operations and whatnot? Sounds pretty complex to me

The human body?

While I'm tempted to say something like the International Space Station, I think it may need to be something bigger, like humanities immune system.

the universe is one giant machine that does everything in the very convoluted process of not doing anything

Toilet.

probably one of the latest supercomputers.

Apple's latest processor.

whatever our bodies are

The biosphere.

A hole In the floor