Date iCal is your one-stop shop for iCal support in Drupal. It provides a plugin for Views to enable exporting your site's calendar as an iCal feed, and a plugin for Feeds to enable importing external iCal feeds into your site's calendar.
This module allow to add day select restrictions in the date_popup widget from
the date moduel that could be displayed as custom form widget, in a entity
with date field or as a exposed filter in a view. The approach to restrict the
selectable days is done used a view display that is used as a data source of
dates that we are interested to allow selectable in our widget. Other days not
returned by this view will be unselectable.