My goal is to be able to type up a content item (e.g. about a play at a local theater) and be able to make a calendar item from the same content. If someone were looking at the calendar for "next week", they would see the play at the local theater and be able to read my content item and the jcomments people have made about it.
Please let me know if this is possible in any well-regarded extension. To explain further, the goal is to be able to put my content item into a calendar, without having to manually copy-paste the text and the url for linking between the calendar item and the content item.
I don't think you will find this functionality in any extension. Content items are just that, unless the extension explicitly uses content items for its calendar entries (and, to my knowledge, none of the calendars do), and you will have to copy&paste from content to calendar.
On the other hand it should be possible to write a mambot that would take the event info from an event and display it in a content item. You would still need to create the event in the calendar and the content item in Joomla but at least the event data is entered only once and consolidated.