Gravity is a responsive minimal coming soon WordPress Plugin with countdown and subscription form. It has clean animation and different backgrounds which changes randomly. It is fully responsive and retina ready.
With this WordPress Plugin you will be able to work on your site/theme while your visitors see the under construction page. When you're done just disable it in the Gravity admin and your new site will be live. You can then keep using it whenever you need to take your site into maintenance mode.
Gravity Responsive Coming Soon Theme