I built KillSwitch (http://Killswit.ch) with the busy agency in mind. Many digital agencies don't host the sites they advertise for and this can cause a problem when there is downtime. It's not uncommon for a client website to go down for hours in the middle of the night while traffic is being sent to the site. KillSwitch monitors the site every minute for connectivity and in the event of downtime notifies stakeholders. If the site is not returned to service after a user-adjustable threshold, the AdWords campaign is paused automatically. Upon restoration of connectivity, it's started again.
This is the most M of MVP's but I've really enjoyed building it. If you have any feedback, I'd be happy to hear it. Josh@Killswit.ch
Stack: PHP with Laravel 4 (http://laravel.com/) Bootstrap 3 Dashboard (Gumby on the homepage) Amazon Web Services Ubuntu 12.04 Local dev with Vagrant & Virtual box Deployment with Capistrano