In collaboration with André Boulouard I created textures for a 'Time Zone Cube' that can be used to display more than 150 city names of the world together with their associated UTC Time Offsets. Daylight Saving Time (DST) can be displayed as an option as well.
The cube is designed to display Time Offsets from UTC-10 up to UTC+10 in 30 minute increments. You can of course use Time Offsets outside this range (UTC-12 to UTC-10 and UTC+10 to UTC+14) by displaying only the last digit on the bottom layer.
You may find an English description and a virtual version of this cube here
I am currently working on translations for a French
The resolution of textures should be large enough if you like to print it on adhesive paper and build you own 'Time Zone Cube'. Edit:
Corrected link of the German 'Time Zone Cube'