We often miss a public event which we would like to attend , by not getting that one invitation in facebook or in any other social network. Social networks generally showcase events based on profiles or groups which create them and the field of reach of these events are restricted to the invitations sent so far.
What if there is a public map, listing all public events by their location ? This app gives users provision to tag events(public) in a public map so that every user will be able to see this event, thus keeping no restrictions for it's reach.
Also, app will have provision to search events based on their type (like social,technical,political, etc) and can use any existing social network account to get access.
I am just proposing an idea. If there is any app that performs the same, please let me know.