I found this very handy ReCSS bookmarklet by David Schontzler (via planet::dojo), which reloads the stylesheets for a page on the fly, so you don't have to reload the whole page for each change. Especially useful for AJAX page, where you may need to do a little clicking to get to see the styles you are changing. I had to fix it up a bit to make it work with Rails and Safari. The fixes were:

• Accept titlecase "Stylesheet" as the value of the rel attribute, which is the Rails default.
• Use URL encoding for the backslash in \?, because Safari for some reason insisted on converting it to a forward slash.

Here is the updated version, which you can drag to your toolbar or save as favorite: ReCSS Enjoy!