Joomla! 3.0 comes with a new design feature for mobile device : the responsive design!
Here are some free (not necessary open source!) responsive Joomla! templates
Be aware! That most of these free templates are NOT responsive. The responsives one are the pro-versions (which require to pay). Thanks GauDau
Joomla template with new features from Avatar Dream framework. You can select the showcase colors and background for your template. Easy to change your background by upload background images to background folder in template folder.
This template from Gavick has been designed exclusively for use with Joomla! 3.0. Further, Meet Gavern features built-in support for Bootstrap.
This responsive template from Gavick too incorporates support for the K2 component, Tabs GK5, and News Show Pro GK4 to meet your current and future information publishing needs - on whatever platform your visitor is using!
This template commes with the new version of Joomla (3.0). With this template, your website looks more than fine across different devices like wide monitors, tablets and smart phones and you are welcome to use it on any project, commercial or not.
JSN Vintage Free
JSN Vintage Free is a cool (but limited pro version) from JoomlaShine.
JSN Kido Free
JSN Kido Free is a fresh (but limited pro version) from JoomlaShine.
JSN Decor Free
JSN Decor Free is a stylish (but limited pro version) from JoomlaShine.
JSN Boot is an excellent Joomla! 3.0 template with clean and modern design with all pro features. It comes with somes modules (galery, form...), super flexible layout, 4 colors vaiation, 3 font styles, 5 menu styles, 9 modules styles and much more.
MX Joofree9 is an simple and cool template developped by mixWEB Template.
Ol Albos is a free responsive Joomla 3.0 template by OlWebDesign. A cool feature is header with photo text and link for each photo. It has 23 module positions. Some features are: Responsive template optional via admin backend, horizontal menu optional as relative, absolute or fixed position...
Pixel Point Creative Carve is a responsive template created on the YooTheme Warp Framework and is for anyone who wants to develop a sleek and professional site. All of our templates are multi-use. This template is focused on skateboarding, but with a few simple changes can be anything you want!
T3 is a new, modern and flexible framework from JoomlArt. You can customize and style your theme in a click with the built-in tool developed for T3.
Gantry is a comprehensive set of building blocks to enable the rapid development and realization of a design into a flexible and powerful web platform theme developped by RocketTheme team. This framework comes with a default temaplate that you can customize...
Vertex is an another powerfull framework developped by Shape5.
Master is the Warp framework default template from YOOTheme.