Add clone of the Milestone widget of WordPress.com in your self hosted WordPress.org site.It uses same CSS styling and should be more or less functionally equivalent to the plugin.
Installation & Usage:
- Install and activate Milestone plugin
- Visit your Dashboard->Appearance->Widgets and add it to your sidebar. You can easily configure it as shown in the following image:
You should also try WordPress Countdown it adds JQuery Countdown easily to your page/post with one shortcode only:
All you need is install & activate it, then start using it by adding shortcodes in your posts/pages. Check its shortcode usage here.