csscss will parse any CSS files you give it and let you know which rulesets have duplicated declarations.
Animations with SASS using the @while directive.
Very good and thorough article on using SVG graphics in mobile browsers. Some great general SVG info as well.
A really slick tool that allows you to understand each of the CSS transition and animation timing functions. It also allows you to build up a custom cubic-bezier easing just using the mouse.
A new typeahead JS library from Twitter.
"A jQuery plugin to provide an alternate text wrapping algorithm."
From the Adobe web platform team.
Symbol font that lets you create a map of the United States using only HTML and CSS.
Create simple tooltips using only HTML/CSS. Written in SASS .
A detailed overview of JS function invocation and the "this" keyword, by Yehuda Katz.
Tools to test your pages for modern and older versions of IE. Nice looking and informative reports as well.