Hi from Italy
Although many watches are created binary, my project was inspired mainly to this:
http:// http://www.instructables.com/id/LED-Binary-Clock-1/, very smart and funny.
I tried to improve the design and to add something personal.
I think it's a good result at the end.
The project is not difficult, requires patience, it requires a little knowledge of electronics and the use of Arduino.

Update 16.04.2015
just thought how would a "cool" kit look a like, so I get an altoids tin box eat all the thinks inside and put all necassary parts inside. ;)
a new project from good old Germany.
I got some of those very popular FM radio modules at banggood.com, and was thinking how to use them.
I found some nice instructables about the TEA 5767 most of them use a NOKIA LCD Display and some buttons to change the frequency or auto scan...., I try those first to learn how to use the TEA 5767, but I didn't like ithem so much it was to boring for me just copy another work and so I think what else could I build with such an TEA 5767 and an Arduino plus some other parts.
I like LED's, to be honest I'm addicted to those LED's. Trust me everything with LED is funny.
I remember those old FM Radios with an "knob" to turn around for adjusting the frequency and showing the frequency on an bar graph like display.
I owned one long time ago there was the indicator for the frequency was a single LED.

I made a xylophone that uses an Arduino Mega to detect when a note is struck, and generate MIDI output. This project is wondeful because I essentially made a xylophone, a drumkit, and any other MIDI controlled sound instrument, with one tool. The following steps  will outline what I used to make this xylophone.