Binary Clock is a clock app with a creative display, its now  available for free on App World. This app displays the time as a binary  coded decimal, with the hours, minutes and seconds of the day displayed  in the colour of your choice. 
A binary coded decimal can be read with each column added up with  each light worth (from top to bottom) 8, 4, 2, and 1, and the column on  the left being worth 40, 20, and 10. For example the time in the above  image would be 16 hours, 9 minutes, and 25 seconds.