Here’s an easiest and fastest way of adding JQuery effect in your default WordPress menus in just a click. Menu Effect is a free WordPress plugin that lets you add JQuery effects on your default WordPress menus (including both drop down main and sub menu) without changing or editing any code.
Social Media Tabs is a free WordPress plugin that allows you to display your Facebook, Twitter, Google+, Pinterest, YouTube, RSS and more in beautiful tab format. You have option to use it as a widget showing tabs or you can slide it out from side.
WordPress plugin repository has a new plugin Jellyfish Counter Widget, it provides you an odometer type counter widget for displaying either a static value or animate it to a set of total. Great for tracking totals, not for counting jellyfish ;-)