If you are trying to get started with creating a Windows 8 Store App, there are some great starter kits that show you how to use several public web service APIs. The kits have sample code to access APIs such as Edmunds, Tom-Tom, Twitter, Tumblr, Yelp, Meetup and many others. Check them out on GitHub.
Mark Rosewater is a friend of mine. He posts a daily comic about Magic the Gathering on card game his Tumblr blog. I modified the Tumblr starter kit to allow users to flip through the last 30 comics on his blog. Check out my “Tales from the Pit” App from the Windows Store (it’s free!).