This is cool. I didn't know you could do this in ASP.NET. The short story is, if you drop a file named App_Offline.htm into the root of your application, IIS will refuse requests to your other pages and send back the contents of the App_Offline.htm file. Short of a fail-over cluster, this is a pretty neat way to deal with the problem. It also suspends the app domain so references to any libraries will be released.