nanoScroller.js - jQuery plugin to implement OSX Lion-styled scrollbars for your website.
strong_parameters gem allows you to "test drive" the new way that Rails 4 is going to treat parameters security. attr_accessible and friends are being deprecated.
celluloid.io interesting approach to multithreaded programming for Ruby.
Letters - new take on debugging logging library for Ruby.
showcase of 40 pricing tables and signup pages can help with with some inspiration for your pricing page.
lenticular.js - Tilt controlled images.
Repo.js - light-weight jQuery Plugin that lets you easily embed a Github repo onto your site.
FullCalendar is a jQuery plugin that provides a full-sized, drag & drop calendar with events etc.
tl;dr Legal - easy summaries of open source licenses.
CCMenu - OS X menu bar application to pull build status of your projects. Support many different CI backends.