Arvydas Juskevicius (say that five times fast) is an independent software developer and hardware hacker based in London (which is where I got a chance to talk with him) who's decided to bring the useful LED signalling capabilities of many modern smartphones into the world of desktop or laptop computers. With his £10 BlinkStick kit (£15 pre-assembled), you get a programmable multi-color LED that's about the size of a flash memory key. Deceptively simple -- it's essentially one giant pixel, after all, which might not sound exciting when you have millions of them on a dense display surface. But that LED light is something you can use as a signal for alarms, or to tell you that you have a message from one app while another is at full-screen, or practically anything else that you can devise software to notice and react to. I get the sense that Juskevicius would prefer that people get the kit version, to help spur interest in actually soldering some hardware rather than just plugging it in. If you're allergic to paying in other than U.S. dollars, the BlinkStick is also available from Adafruit Industries. Watch the video below to see it in action.