This will only work for those of you using Firefox. Though if you're a die hard WP member you'd get Firefox just so you can use this add-on. You can use it to change the colours of various parts of the site.
This is it here: https://addons.mozilla.org/en-US/firefox/addon/color-that-site/
1. After you have it installed, go to tools up the top of your browser and "color that site". The toolbar will appear to the left of your browser.
2. Click either go or new edit (can't remember which)
3. Go to the background colors dropdown.
4. In the HSL mixer menu move the middle selector bar all the way to the left (this is the selector for colour saturation) This will make all the colours in the background of the site grey.
5. Now use the third/bottom selector bar to determine the darkness of the grey you wish to apply. You can press preview down the bottom at any time as you go.
6. Once you are happy with the previewed shade go to the settings tab and set "scope of definition" to "domain"
7. Click "save" up the top and the new look of your WP page will be applied.
Feel free to play around with all the colours for the background and foreground if you like, though it takes a bit of tinkering. Maybe we can find a way to share settings as we come up with more colour combos.
Grey is just the easiest colour adjustment I found to make at the moment. Mine is a nice cloudy day grey.