This code provides a sidebar widget version of the Countdown to Backpedaling from wecantknow.com:
Download ctb.php and put it in your wp-content/plugins directory. A "Countdown to Backpedaling" widget should then show up in the Widgets control panel, and you can drag it to wherever you want.
Download ctb.html and insert it in your site. The details of that depend on what you're using, but hopefully you can just insert it anywhere that you can put HTML.
This widget is pretty minimal, although thankfully self-contained. The main configuration knob is the "show_secs = true" line near the top. If you find the seconds display annoying, just change "true" to "false".
I may add some additional configuration, or integrate this better into WordPress, if I don't run out of time before the world ends.