Orbit

Orbit is a resposive free theme. It comes with 9 widgetized areas, 3 different page layouts, image slider in Front Page, Google Fonts, Social Networking links and free support in English and Spanish: http://bitado.com/soporte-orbit/

Orangy

Child-Theme of Twenty – The 2012 theme for WordPress is a fully responsive theme that looks great on any device. Features include a front page template with its own widgets, an optional display font, styling for post formats on both index and single views, and an optional no-sidebar page template. Make it yours with a custom menu, header image, and background.

Orange

Minimalistic two-columns, fixed-width, seo optimized theme for WordPress. Compatible with WordPress 3.1 features, valid XHTML & CSS, custom widgets(Twitter, Flickr, About us).

Opus Primus

A WordPress Framework Theme … the first work. It works first. Designed and developed to be extensible and easily modified, based in the principles of decisions not options. Opus Primus supports all of the current Post-Formats as well as auto-magically converting between one, two, and three column layouts. Enjoy the mobile friendly menu integration of SlickNav and improved responsive video performance with FitVids. You have access to custom backgrounds as well as a flexible custom header, too. Feel free to visit the Opus Primus website for more details and information about the theme and how it is built. You will also find tutorials on how to modify and work with Opus Primus Child-Themes.