Not ready to sand/embed your LEDs, but they're too bright to look at? This Instructable is for you! I'm fiddling around with my Arduino and TLC5940, and I'm getting a headache from staring at them. But, I don't want to sand them down, or otherwise permanently diffuse them, and putting them behind a sheet of paper or typical diffuser won't let me clearly see the specific patterns I'm trying to achieve.
http://www.instructables.com/id/Quick_Temporary_and_Cheap_LED_Diffuser/