Material Design Lite
I've always been a fan of pixels and clean lines, a lot of my old site designs were minimal with a lot of emphasis placed on a pixel style look and feel. After a many many year break from web design and much more of a life focus on cellphones as opposed to computers as a main interface for the internet I came across Material Design by google. I wanted to play around with it, and found MDL Lite ( https://getmdl.io/ ) and fell in love. There is much to love about the simplicity of a front end style that is as easy to implement as 3 quick additions to your head
<link rel="stylesheet" href="https://fonts.googleapis.com/icon?family=Material+Icons">
<link rel="stylesheet" href="https://code.getmdl.io/1.3.0/material.indigo-pink.min.css">
<script defer src="https://code.getmdl.io/1.3.0/material.min.js"></script>
And you are ready to go!
From there head to Components ( https://getmdl.io/components/ ) and hack away.
For a base, the Layouts section is a perfect entry point, from there adding individual components is as easy as finding what you are wanting to use, and copying the code. Lots of goodies there!
http://blokz.io/ features a MDL design, as well as http://sn0n.github.io/ both of which are getting a makeover in the coming days, so stay tuned!