Drag and drop interface builder

If you're looking to startup with your frontend code and quickly want to setup the base with bootstrap, Layoutit is a great way to start with. Link here.

Jquery plugins for highly configurable grid contents!

Gridster.
An awesome jquery plugin to make a dynamically configurable grid layout.
It works in IE8+ and doesn't disappoint at all.

Xlune

Wookmark

Masonry

Freetile

Page layout like reading a book!

Link here.
This cool flipping page layout is inspired from flipboard.
It does not break in browsers that do not support it but just gives a simpler layout.
The even more cooler thing is that, it works on any size window. So, is compatible on
smart phone and tablet screens too.