SharePoint 2013: Hello World remote app using CSOM

http://code.msdn.microsoft.com/officeapps/SharePoint-2013-Hello-0fd15fbf#content The sample demonstrates how to read data about the parent SharePoint site on which the app is installed by using OAuth and the SharePoint client object model (CSOM). Page load stores context token string in link button command argument to provide access to token on postback

Restore Sign-in as different user in SP2013

http://nickgrattan.wordpress.com/2012/07/23/sign-in-as-different-user-and-sharepoint-2013/