Again with the custom post type extensions. This function lets the native WordPress wp_get_archives() [^1] [^2] know about public custom post types; just add it to the functions.php of your theme. Of note: the builtin link post type can be included at the array_merge() point; I just had no use for it.
By default or design, the WordPress function get_calendar()[^1] does not handle post types other than post. I've updated it as the standalone function ucc_get_calendar() to allow it to accept a $post_types array; the included filter function ucc_get_calendar_filter() will allow for seamless integration via functions.php without requiring additional editing of Theme templates. (Note that the filter will also apply to the Calendar Widget's output.)