Google Calendar allows you to invite other Google users to share a calendar with you. If you are co-operating with a team of people, this tool is priceless. This way, all group members know when each member is working. You can also enter the location of a meeting so that everyone knows where to go.

Google Calendar also allows you to set authorization levels on each calendar to control the amount of power you grant to other people. You can let them have full access to create and modify event details at that specific time or set it up so they can only see an event but not edit it.