Kevin Wick has posted a very nice sketchy-styled Axure library.  I highly recommend it.
Prototyping in a very low-fidelity visual style generally helps your stakeholders provide feedback at the right level, as discussed in this article, and has been adopted by many other design tools, notably Balsamiq.

Web applications and sites these days are using many social features. This library, compatible with Axure versions 5.5 and up, contains many of the standard widgets you will need to prototype basic social functionality.
You’ll find a lot more than nice looking stencils – these widgets have polished interactivity, for your prototyping and usability testing [...]

About a month ago, the folks at Zurb published a nice article about sketching wireframes.  I went ahead and purchased some new sketching items including a nice thick sharpie and a cool gray “dropshadow” pen.
The difference in my sketches is incredible.  Zurb hits the nail on the head, saying, “Although we advocate keeping things as [...]