How to have recurring date events?
As of 2016/03/04, these are open issues in Drupal 8.  See Support for end date and D8: Date repeat feature requests.  The decision was made to move these from contrib into core, but they are complicated issues, and unfortunately touch the exact same portions of code, so working on them simultaneously is difficult.

As of 2016/12/07, support for end date is officially part of core, starting with 8.2.0.  It is looking like the date repeat feature is going to end up in the datetime extras module as part of contrib, and not core.  However, work on this is still preliminary.