This might seem like just a simple grey clock, but it has a clever rolling mechanism that allows it to display 24 different time zones. The hands work independently from the body, so you can roll the clock to whatever time zone you wish, and then roll it back to the local time. Only the side shows each time zone, leaving the face free of any extra graphics.
The 11+ World Clock is available from Leibal.
Available in Grey, Blue, or Orange.