There is a very easy way to stop a website and provide your users with a nice “under maintenance” or “offline” page.
Just create a new file in the root directory of your website and call it “app_offline.htm”
Whatever the request to your site, users will always be served this page.
Is you ever use publishing via visual studio, you will notice that during the publish this file is also created to let your users know maintenance is occurring on your site.
To make the site available again just remove the file.