I don't prototype designs using photoshop. I go from sketching on a paper (or just imagining things in my head) straight into HTML and CSS. That means that I quite often run into having to come up with a new tree with 960gs, jQuery, Less and an initial HTML5 page in order to sketch out ideas. This process is repetitive and time consuming. Which is where bootstrap comes in (and this is why I did it for myself, in hopes that others might need the same thing).
bootstrap, you're getting a basic trunk with all the pieces I mentioned above (html5 + jquery + 960gs + a less file). You can then use the bootstrap.sh to get the latest versions of 960gs and jQuery. All you have to do after cloning, is editing index.html and starting to work.
git clone git://github.com/fredoliveira/bootstrap.git newsite cd newsite bash bootstrap.sh mate . (if on a mac using textmate)