You can subscribe to read-only WebDAV calendars, like holidays and sports schedules, in BusyCal by selecting Subscribe to WebDAV Calendar or Find WebDAV Calendars from the View menu. Once subscribed to a WebDAV calendar in BusyCal (and iCal) you can sync the calendar to your iOS device through iCloud. WebDAV calendars will not appear on icloud.com, but they will appear in BusyCal (and iCal) and on your iOS device.