Twitter Bootstrap is a CSS and Javascript framework for creating light-weight web-sites. It provides useful layouts and UI components and supports both desktop and mobile browsers. Normally you use it with JQuery and server-side programmming tools like PHP or JSP. It doesn’t rely on Twitter, but was originally created by some gurus employed by Twitter. Some interesting links:

• Download: Bootstrap.
• Marketshare: Powering 1% of the web.
• Market for Bootstrap Themes