I've put together an extension which will allow you to turn on and off your instances of Radiant.

Enabler will allow you to post to your sites to disable and enable it's ability to serve content. You might use this extension if you host sites for your clients and they pay to you a monthly fee for service. If your customer has refused payment or if their payment bounces you can post to the_website.com/admin/disable/your-api-key and the cache will be cleared and the site will serve a simple message that the site is down.

You can change the message by adding a message parameter to your disable post. Just post to the_website.com/admin/disable/your-api-key?message=Please%20pay%20your%20bills

This will allow your customers to continue to login to the admin area but they won't be serving up any public content until their bill is paid and you post back to re-enable the site.

It's built for Radiant 0.9 and you can just gem install radiant-enabler-extension and load it up in your environment.

This isn't an extension you'd use manually and you'd probably want to tie it to a billing service such as Spreedly so that a site is automatically turned off when there is no payment.

To prevent ~~delicious~~ malicious hackers from scanning sites for this extension it will respond with a typical Radiant response for the URL rather than a 403 Forbidden error code as you might expect. If someone posts to your site with an invalid key, Radiant will simply respond with the usual 404 from your FileNotFound page.

If you think it could use a feature to turn off admin access too, just code and send me some pull requests.