Currently the possibilities to create a resource's calendar are very limited and the calendar can only cope with very straight forward working hour models.

It would be good to have an option to enter a custom series, such as "Work hours 8 AM - 2 PM on Friday, every other week" or "Workfree time every first Friday of the month".

It should also be possible to enter overlapping series. Currently a new series will always erase the future instances of an existing series and it is not possible to have to one active series for "Monday through Thursday 8 AM - 5 PM" and another active series for "Friday 8 AM - 2 PM, every other week" and one more for "Friday off, every other week".