Resources for Rapid Web Prototypes

Alot of times, I find myself in a position where I have to put some prototype together of some bit of functionality so I can convince either myself or someone else that we should use it in an upcoming project.  Whenever I need to do one of these "Rapid Prototype" type of projects I always end up needing to put together a little website template to show off the functionality (presentation is important when trying to get a sign-off).  I've started using some free templates I found over at Smashing Magazine to help me get to the Rapid Prototyping faster, instead of sitting around making a pretty site from scratch.  

Here are a couple useful links I've found:

100 Free High-Quality XHTML/CSS Templates - Bunches of templates ready to use, most if not all are licensed either under MIT or GPL.

Company Dark Blue Template - Nice little conservative business company template.

Free CSS Layouts and Templates - These are nice if you are just looking for the scaffolding of the site without any artwork.

Jquery - Must have for most of my current web work, also see this post at Encosia for tips on having Google Host your jQuery (all the cool kids are doing it...)

Block UI Plugin - Great for modal dialogs, even has some cool support for Growl like popups.

jTemplates Plugin - Great for client side templating of JSON data.

Encosia's Posts on jQuery and .Net nuances - Great place to start if you are new to jQuery and how best to use it with .Net

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