User Calander
 

User can create their own calander, chose whether or not to make it publicly viewable too.

Usergroups are allowed X amounts of calanders etc.

Not exactly what you want, but you do know that you can set up a calendar that each user can use as his privat calendar (because everyone can only see his own entries) ?

Yes I do :)

But, the main use for me (I do not know about others) is for inner communities to set up their own calanders. One example maybe a clan having a calander of matches etc.