A MIT-licensed template for HTML5 websites that includes a lot of CSS and JS tweaks and optimizations. It provides support for JQuery, Google Analytics, old browsers, etc.
Build a Feed You Can Cut 'n Paste, will help you format a feed's display with the information you want to use on your web site. All you need to enter is the URL for the RSS source.
a lightweight Javascript library highly documented and well tested, that will help you get shit done, fast. We took all the good ideas we could find from our Python, Objective-C, etc. experience and adapted it to the crazy world of JavaScript.
Ever want to add drag and drop to your website? How about a cool animation or fade? Rico is an free, open javascript library that makes adding these features easy. Check out the demo, it's pretty slick.