This is a 'would be nice' rather than a 'must have', but I don't know how difficult this is, so I thought I would suggest it.
I'm using Clock on a site to visually remind visitors that businesses or other users are in different time zones. This will assist them with making on-line bookings.
At the moment I display the site visitor's time at the top of a list of times for well known cities.
It would be nice to have the option to sort the list chronologically, automatically, including the entry for the visitor's time, to emphasize who is ahead/behind them in time.
This would also make it clearer what locations are yesterday/today/tomorrow compared to them, even when displaying just the time with am/pm.