Visual Studio 2013 offers several authentication options for web applications as described in the article below. http://www.asp.net/visual-studio/overview/2013/creating-web-projects-in-visual-studio#orgauthoptions
The following walkthrough is great for setting up authentication for a web application against an ADFS instance. http://www.cloudidentity.com/blog/2014/02/12/use-the-on-premises-organizational-authentication-option-adfs-with-asp-net-in-visual-studio-2013/
The same approach can be used to setup authentication for a web application against Windows Azure Access Control Service(ACS).
The metadata URL can be found in the windows azure management portal for ACS, in the Application Integration section
For “App ID URI”, you can leave it and the default value will be automatically populated or you can configure this to be the realm for your application. Click Ok and your web application is configured to authenticate against Windows Azure ACS. NOTE: http://blogs.msdn.com/b/cie/archive/2014/02/21/errors-id4175-and-wif10201-in-context-of-acs.aspx has a couple of errors you may run into.