The first time I gutted a dead harddisk and got a close look at all the neat shiny bits inside, I remember one of my first thoughts was: "I bet this stuff could be turned into some cool jewellery."
So that's what I did.
Here's a write-up so you can do it too.
Time: A few hours.
Caution: Requires ability to use saws without cutting off own fingers. Or someone else's fingers.