Remember Google Redesigned (nee Gmail Redesigned), the sexy skin that made Gmail look so purty? Well, Google itself just rolled out 30-odd themes for Gmail, some of which are seriously cool.
To browse the choices, sign into your Gmail account, click Settings, and then click the new Themes link. Pick one you like and click it: You'll see it applied immediately. (Best bets: Graffiti, Ninja, and Terminal.) Of course, you can always go back to Default or Classic if you don't like the new stuff or you're feeling nostalgic.
Okay, so this has little to do with productivity, but I will say this: about time, Google! Gmail's Web 1.0 facade was really getting old. (Meanwhile, the aforementioned Google Redesigned site has been down for days, so the timing really is perfect.)
What do you think of the new themes? Neat? Garish? Unnecessary? Hit the Comments and name your favorite(s), if you have any.