Zown is a very simple timezone and weather tracking app. We set earth longitude as X axis and daily 24 hours timeline as Y axis. Thus youre able to see the time differences in a new way.
Also, once you added enough cities in the app, you can scroll on X axis infinitely. Just like having the earth spinning under your fingertip.
With the time cassette function, its possible to add a time offset to all the cities. Its a great way to time travel.