As a developer I always wanted a CSS framework which will not only ensure that the layout of my application is up to the standard but also it looks good. Something more Web 2.0 and that too very easily. Bootstrap is the answer to all my requirements. It has the power of grids and layout like the 960 grid and on top of that it has its own powerful elements using which I can build nice looking user interface in minutes.
Source: http://twitter.github.com/bootstrap/

Bootstrap is an excellent tool which can be used easily to create some wonderful user interface looking extremely professional. It provides a simple yet very flexible css, javascript and other tools which can be implemented with code or framework and you within minutes can create cool layouts and popular user interface.
It supports responsive layouts, grid systems and mix very well with custom css. Has nice custom jQuery plugins and a growing library. On top of that if you want to make your website mobile friendly – well this is a good tool to do that.
It provides theming to baisc css elements which makes sure you write very less and easily get professional looking elements. For example if you add these classes to a table “table table-striped table-bordered table-condensed”, you will get a table which has stripes and a border and condesed. Yes, that's all you need to do to get something like this:

Or may be even a simple div tag like this “<div class="alert alert-success">” which give you a ready made alert like container where you can print messges.

So, feel free to explore this amazing library and you can even refer to the video tutorial by Webdesign tuts which will nicely explain how to implement and use this library.
http://webdesign.tutsplus.com/tutorials/complete-websites/twitter-bootstrap-101-introduction/