If you have to keep track of the time in more than one location, either because you have co-workers in other locations, family members in other locations, or some other reason, then you may want to take a look at a new jailbreak tweak called World Clock 7
by iOS developer Gilles PETIT.
Shown above, World Clock 7 will allow you to have up to three different times on your Lock Screen at once; each for a different location in the world. Your main time shows in the middle as usual, but the tweak also adds two more customizable times, one on the left side of the Lock Screen, and one on the right side of the Lock Screen.
World Clock 7 adds a preferences pane to the Settings application where you can configure what times you would like to see, and more:
Here, you can enable or disable the tweak on demand, configure the time zone you would like to use for your left-side clock, configure the time zone you would like to use for your right-side clock, and you can even title the right and left clocks to be anything you want them to be (rather than just the name of the location).
Notably, the tweak also changes the font of your Lock Screen clock, which does take a little getting used to, but at the same time, the added functionality of being able to see three different times at once could certainly be useful in a pinch. If you want to give World Clock 7 a try, it's available for free in Cydia's BigBoss repository for $1.00. It does require iOS 7 to be installed.
World Clock 7
iPhone 5 running iOS 7.0.4