Recently I discovered Bootstrap from Twitter. As mentioned on the website "Bootstrap is a toolkit from Twitter designed to kickstart development of webapps and sites. It includes base CSS and HTML for typography, forms, buttons, tables, grids, navigation, and more." And it is very nice.
But you never truly know how good a tool will be until you try it. In the last few days I have used Bootstrap for two small projects – one internal project at SiteHost where I work, and then again today when I built a webpage for my mothers shop in a couple of hours: www.chandelle.co.nz.