I recently bought myself a Raspberry PI Zero and it's an amazing little device. At first, I attempted to turn it into a NAS drive, since I have a lot of external hard drives sitting around gathering dust. Unfortunately, the PI was too underpowered to handle the bandwidth that I was expecting.
I came across a cool little project called "PI Hole". Pi Hole is a DNS level adblocker. In simpler terms - it blocks those annoying advertisements you see on websites, youtube and social media.
So far, it's been amazing.