lake.js is a jQuery water waves plugin that takes an img element and inserts a canvas element displaying the image and its flipped reflection directly after the img element.
Filtrify is an advanced tag filtering plugin that you can search tags within tags and filter items by multiple tags from different categories and get a live feedback on the number of items containing related tags.
It uses native <audio> where available and an invisible flash player to emulate <audio> for other browsers. It provides a consistent html player UI to all browsers which can be styled used standard css.
OIPlayer 'attaches' itself to all video and/or audio tags it encounters. Besides the general configuration of the plugin itself, it uses for each individual tag the attributes the respective tag has like poster, width, controls, autoplay etc. Easy implementation
GradientText is an ultra small, easy to use jQuery plugin that will give your standard H1, H2, H3, etc. headers a gradient text color. GradientText automatically converts your text to a HTML5 <canvas> tag with the gradient you specify, and also allows for shadow. The font will stay the same as defined in your CSS.