We are looking for the best approach to displaying calendar items in our school district site.
Currently we have a calendar view which displays the calendar with all calendar items included (from about 28 calendars included in all). Our content type is a Calendar Item which has a related taxonomy for the calendar category (a required single level taxonomy category only used for Calendar items)
Initially we would like to create one view with exposed filters to allow display of one or more individual calendars. Ideally this same view could be used on a school page/and menu (each school has their own menu) filtered for their school only.
Is using an exposed filter the way to go on this (if so, any suggestions), if not how else might we go about providing an easy way to display calendar items in one or more calendars?
Our environment includes Drupal 5.x, Views 5.x-1.6, MySQL database 5.0.51a, PHP 5.2.4-2ubuntu5.3...
We are also using Calendar, Date and Date API 5.x-2.5 and we make heavy use of Taxonomy Access Control 5.x-2.x-dev rather than groups for our individual school content and access control.
You can see some issues we have faced on this at http://drupal.org/node/362757

Comments
If you use a taxonomy term
If you use a taxonomy term as a filter, I think you can configure it so that http://mydomain.com/view-name?tid=1+2 shows the calendar items tagged by tid = 1 and tid = 2, which allows for multiple calendars. I guess then if your select is a multiple select, you'd be able to show that functionality in the exposed view.
Of course if someone tried to select 20 calendars to display at once, the potential url is http://mydomain.com/view-name?tid=1+2+3+4+5+...+19+20 and the SQL query is likely to fail (I think each extra tid creates an extra join...)
Dave