Luca’s Theme is a free responsive WordPress theme and it works for BudyPress too. It was based on Twitter Bootstrap and has a quite clean and responsive design.
Features:
Responsive theme for WordPress and BuddyPress
Built-in Custom Post Type Nivo Slider
Custom Author Byline Implementation
Modern CSS3 Style Techniques
Custom Homepage Template
Custom Full Width Template
Left Sidebar Template (Your sidebar, your choice!)
Custom 404 Page Including Popular Posts