UX Challenges - Done reading about UX? Start doing it.
Timezone.io - Keep track where and when your team is.
Uxcel - The easiest way to learn UX/UI design
TimeZoneNinja - Scheduling meetings around the world just got easy
uxtoast: Learn UX Design - Become familiar with design laws and learn how to use them.
Timelines - Timelines is an app to track & visualize time.