Minimalistic is a Jekyll theme for GitHub Pages

Framework for creating rich WebGL-enabled applications using JavaScript and Ruby. Can be used stand-alone to create static JavaScript documents, or integrated seamlessly with Ruby on Rails to build dynamic WebGL applications.

A Jekyll theme inspired by classic 8bit games.

Strata Academic is a Jekyll theme for academic GitHub Pages

validate-website is a web crawler for checking the markup validity with XML Schema / DTD and not found urls.

this gem has been discontinued, from now on you should use the site_validator gem

Gem to ease the pain of managing capybara driver config and provide a home for common utils and patches

Renders markdown via rdoc-rouge, an RDoc and Rouge bridge. Able to use fenced code blocks like github, and includes a default pygments stylesheet.

Open Hub Jekyll theme

Open Project Jekyll theme

Lightning Sites gives you beautifully simple deployment for your ~/Sites folders, inspired by Fastlane. We support all deployment setups.

Rack middleware that validates HTML with w3c validator and displays result in page.

Allows testing vor valid html (including html5) and css. In addition you can configure the gem to use a locally installed validation service instead of the online w3c servers

Aurora is a clean, responsive Jekyll theme for GitHub Pages with immersive design

Tools to help validate web pages. Gathers validation results from multiple sources, providing a single interface for both requests and responses.

Validates HTML and accessibility. Follows FM&T Standards: http://www.bbc.co.uk/guidelines/futuremedia/technical/semantic_markup.shtml

Bubbling Ale is a Jekyll theme, designed specifically for Github Pages

Epic validator, wraps validation for HTML, JavaScript and CSS.

A fork of the Hacker theme for the Foxfire Blog.

HackerMatrix is a theme for Jekyll.