Bookmarklet for disabling styles
The following Javascript will disable all styles on a page, leaving the raw HTML markup.
for(i=0;i<document.styleSheets.length;i++)
(document.styleSheets.item(i).disabled=true);
el=document.getElementsByTagName('*');
for(i=0;i<el.length;i++)
(el[i].style.cssText='');
You can bookmark this link (Right click, Add to Favourites...) to have a "bookmarklet" that will disable styles on the current page.
Disable Styles
You can refresh the page to return to the stylised view.
Example Styles (click the link above to disable styles):
font-size:20px; color:red; text-decoration:underline;
font-variant: small-caps; font-style: italic;
background-color:lightgreen;