A major problem of prototyping in code is that the prototype may be mistaken for a (nearly) finished product and that the focus shifts from the interactions towards colors and fonts.
Some mockup tools (Pencil, Balsamiq) provide sketchy stencils to create mockups which look not finished. I tried to recreated similar style which can be applied to Bootstrap Designs as a theme, including styles for buttons and widgets.
Image: …testing as drop-in with the Freifunk-Splashpage
UPDATES: 21.10.14: Added Freifunk-Example