#1: Free Programming Books
Exactly what it sounds like. This project posted by Victor Felder was initially a clone of a StackOverflow list by George Stocker, updated with new content. Listing all the programming topics and languages on the list would take far longer than a small blurb, so click here and browse to your heart’s content.

#2: Ghost
Ghost is a free, open, simple blogging platform that’s available to anyone who wants to use it. It was created and maintained by the Ghost team, John O’Nolan and Hannah Wolfe. Ghost’s simple design and complete customization gives bloggers the tools to spend less time messing with their blog and more time blogging.

#3: Odometer
This HubSpot creation is a JavaScript and CSS3 library for smoothly transitioning numbers. Odometer’s animations are handled entirely in CSS using transforms, making them extremely performant, with automatic fallback on older browsers. The library and largest theme are less than 3KB when compressed, and all of the themes can be resized by setting the font size of the .odometer element.

#4: Full Screen Mario
Itsa Mario! In the browser! Classic Super Mario fans owe Josh Goldberg a debt of gratitude. This HTML5 remake of the original Super Mario Bros. is expanded for wide screens, and even comes with a set of cheat codes. There goes any chance of downtime productivity during the workday. You’ve got a lunch date with Bowser.

#5: TextTeaser
This automatic summarization algorithm by Jolo Balbin combines the power of natural-language processing and machine learning to produce results. TextTeaser’s API extracts the most important sentences of an article to provide a preview of what it’s about.