Orchard Bootstrap Machine is a flexible multi-zone theme that provides a solid foundation to build your site. It features 20 collapsible widget zones and is flexible enough to cover a wide range of layouts.
If you like, you may add references to BootSwatch from Administration > Settings > Theme Options to get about 16 different variations of the theme.
Here's an example of using superhero:
Customer Header Content:
<!-- Use cerulean, cosmo, cyborg, flatly, journal, readable, darkly, lumen, paper, sandstone, simplex, slate, spacelab, superhero, united, or yeti. -->
<link href="https://maxcdn.bootstrapcdn.com/bootswatch/3.3.5/superhero/bootstrap.min.css" rel="stylesheet" type="text/css" />