|Blink(1) USB Light|
After a lot of searching, I ran across the Blink(1) by ThingM.
The guys over at ThingM really know what they're doing, even the box is well designed. Simple, clean, and very apple-esque:
This little USB "Status Light" comes with some pretty cool software, but the most impressive part is that it's entirely open source. They even have a Node.js library, which works quite well. Even better, for simple applications, they have a very simple control program which hooks into services like IFTTT, or even works off of simple shell scripts which can return a status color code.
Overall my experience with the Blink(1) has been very great. It's simple to get started with, and very open and easy to make do exactly what you want. Even if you don't want to do development, it's super simple to make it respond to things like searches on twitter, getting emails, or even just responding to music. Being from the DAMMIT era, this is certainly a worthy piece of technology.