In my always-continuing quest to find the perfect online calendar display/management solution, I have found the next level of calendar display/management bliss.
Previously, I was pinning all my hopes on Drupal's very robust, but often complex and confusing, Calendar.module (in use by almost 50,000 websites—and for good reason—it's extremely adaptable). The module provides many different displays, and gives you the ability to link directly to a specific day/month/week... but it (a) is relatively slow to allow switching from month to month, (b) requires a rather complex view, with arguments, which can be confusing for first-time users, and (c) it takes patience to theme it well.
I love the Calendar module, and I still use it on a few sites where necessary, but I've found a new contender that has nothing to do but improve; that condender is the FullCalendar module, which is based on the great fullcalendar.js jQuery-based calendar library by Adam Shaw.
This is IE. It's easy enough, though, to add better styling to a fullcalendar.
FullCalendar is simply a views display that takes a list of event nodes (as long as your node has a date/time attached, it will work), and displays them in a beautiful calendar display that works across all modern browsers, and even most mobile browsers (I've tested Android, iOS 4, FF, Chrome, Safari, and IE so far).
I had a little trouble getting the calendar to display in IE6/7, but I supplied a quick patch to fix that issue.
One thing I have yet to test is the performance of fullcalendar when displaying large batches of calendar items (in this case, calendar.module might be better—if you need to show thousands of events on a calendar from many years prior). The biggest calendar I have right now displays about 200 items. As time goes on, I could either simply let the list build to the point where fullcalendar slows a bit, or limit the date range so events from only the past few months show.