I needed a tool that allows me to convert times between different timezones. There are plenty of programs that tell you the "current time" in a given timezone, but it's not much good for converting.
Anyway, this little app just sits in your tray and when you double-click the icon, it pops up a window for you to enter the date. Then just select the source/destination timezones and it'll show what time it is in that timezone.