To house all the pieces, you need a case. These come in all different sizes, shapes, and colors. Some of the cooler ones look like an escape pod Superman came to Earth in. Others are a big black box.
Some are pink...
Some are green...
...But most are big black boxes. Mine's a big white box! I used to have a box with some red accents that was much bigger than this, but since I was doing a big PC upgrade, might as well take one from work, eh?
RGB- It's the gamer's kryptonite! It's pointless and pricey but god damn does it look awesome!
These fans came with the case. Unfortunately I can't set the color to just be purple or make them do cool effects, but it's something.