I found this handy feature of the ASP.Net 2.0 Framework today: If you want to disable all access to your ASP.Net 2.0 web site you can just place a file called App_Offline.htm in you root directory. All requests to any folder of the site are directed to this page, so you can write a friendly 'Down for Maintenance' message there and be comfortable knowing that no one will access the site while you're updating files or the database. The web application is completely unloaded from the web server so it can also help when you want to instantly unlock an Access or SQL Express database that resides in the app's App_Data directory.

Jimmy