taultunleashed

It would be nice to have a calendar:

GroupCalendar allows guilds or groups of friends to share an in-game event calendar. The guild can post raid events and members can post events for dungeons they need to do quests for. Additionally, players can provide feedback to the event's sponsor saying that they will or won't be attending an event.

http://wow-en.curse-gaming.com/downloads/details/1958/

Well unless everyone in your guild is running the script there won't be the framework to make something like this. WoW can because they made the framework to have custom data channels between players in order to sync up the information. In LOTRO you would need to do it outside the game with a 3rd party server most likely.