Twenty Eleven Theme Extensions by Mike Walker is an easy-to-use plugin designed for use with the latest default WordPress theme, Twenty Eleven. It adds a set of customizable features for the theme, designed to add more flexibility to the theme’s design without having to modify the template files.
Features include:
Add the widget sidebar to all pages, and single-post pages.
Optionally center the navigation links at the top of single-post pages with a sidebar.
Change the default height of the banner image in the header.
Adjust the alignment of sidebar widget titles.
Automatically turn sticky posts into single-line headlines to alert your readers of something important.
Add custom CSS styles for your site safely in a place that won’t be overwritten when you update WordPress or Twenty Eleven
Plugin homepage: http://moztools.com/wordpress/theme2011-plugin/
Download and info: http://wordpress.org/extend/plugins/twenty-eleven-theme-extensions/