The Golgi apparatus, also known as the Golgi body, is like a post office. It receives things and sends them off to different places. I've broken it up into four steps:

1. It receives proteins from the endoplasmic reticulum or from anywhere in the cell.
2. It sorts and packs up proteins into another  vesicle. 
3. It labels the vesicle. The label says where the vesicle needs to go.
4. It sends the vesicle to its destination. This destination could be somewhere else in the cell, or to another cell somewhere else in the body.

These organelle do a lot of things. What gives them the energy to do all of these things? Let's look at the super-duper mitochondria.