#1: Card 

Developer Jesse Pollak’s creation is making credit card forms better, one line of code at a time. Card will take any credit card form and streamline the checkout process using only CSS, HTML and Javascript, no images required. 
#2: HTTP API Design Guide was featured in last week’s Top 5 trending projects.
This JavaScript color generator by David Merfield generates random colors by passing an object to influence the type of color it produces. The object is then influenced by hue, luminosity, count and format to return multiple arrays of distinct, complimentary and contrasting colors.
Popping is a collection of animation examples for iOS apps. Created by André Schneider, almost all of the examples were built using the Facebook Pop animation engine. It should inspire you to create some great-looking UIs to delight people who use your app.
Algorithms.js is a collection of classic algorithms and data structures implemented in JavaScript for the purpose of, as developer Felipe Ribiero puts it… SCIENCE! The intention is to blend academic concepts with the JavaScript bits of insanity, applying Atwood’s Law to CS101.