The Sartorialist - Responsive Blog
I've been trying to find things to practice on recently. I went with The Sartorialist because it's an easy option as I know the site and subject. Although The Sartorialist blog has great content the design isn't up to much, lacking a responsive design.
This mobile design is just a start for now and I'm planning on working out how to do feature posts, fix the sharing function and include advertising. I read somewhere that the owner, Scott, makes at least $100,000 from the sidebar advertising for brands such as American Apparel etc, so it's important for it to work on mobile also. This is something that The Guardian are experimenting with relentlessly at the moment.
Will update this in a few weeks with something more.