Sparkfun's AVR Stick uses blue LEDs to drop the 5V output from the microcontroller to ~3.3V instead of zener diodes.
The LEDs make it easy to tell if the device enumerated correctly. Plus blue LEDs are available at Radio Shack, but
3.6V zeners are not. However this level conversion trick isn't mentioned on the wikidot hardware page.
Why? Do zeners work more reliably than blue LEDs for level conversion?
http://www.sparkfun.com/datasheets/Widg ... ck-v12.pdf