The first step to this process is to define the list of items to be automated and propose rules for dates. Through Prologue and Season One, there were some inconsistencies with when certain items were enabled/disabled. For example, in 2007, Delin became winter on February 20th, but the only mention I can find for this in 2008 was on March 8 (due to a post from Erik on UruObsession).
Below is a proposed calendar of items. The dates I've collected thus far originate from UuObsession, DRCSite, Guild of Greeters, and MystLore. Assistance in verifying or improving on this data would be great. For example, I remember that the Kadish helmet vanished and then returned sometime during Season One but either my memory is wrong, or records of this are deficient.
I expect that http://en.mystlore.com/wiki/D'ni_timeke ... algorithms should be helpful in ensuring that D'ni holidays are computed for our modern calendar correctly. http://uru.outoforder.cc/FrontPage contains documentation for SDL values that haven't changed since Until Uru - if there's a newer resource that covers all of the MOUL additions, I haven't seen it and a link would be great.
Proposals for any other additions to the list would be great too.
Spoiler
Clothing: Viking Helmet
Location: Kadish Tolesa
Added : December 20, 2006
Removed : Unknown (GoG claims "Still available")
Proposal: Make monthly random, 40% chance to appear
Clothing: First Month Shirt
Location: Great Stair, City
Added : December 21, 2006
Removed : February 1, 2007
Proposal: Make available 1st month per shard
Clothing: St. Patrick's Hat
Location: Closet
Added : March 7, 2007
Removed : Unknown (GoG claims "Still available")
Proposal: Make available for 21 days with St. Patrick's in the middle
Clothing: College Basketball Jersey Shirt
Location: Closet
Added : March 11, 2007
Removed : Unknown (GoG claims "Still available")
Proposal: Make available during normal March Madness week(s)
Clothing: Santa Hat
Location: Closet
Added : December 24, 2003; December 21, 2006
Removed : December 26, 2003; January 1, 2007
Proposal: Add December 14, remove w/ New Year (same as tree)
Decor : Fall Decorations
Location: Neighborhoods
Added : November 22, 2003; October 26, 2007
Removed : Unknown
Proposal: Add 1 week before Halloween, remove on Saturday after Thanksgiving
Decor : Christmas Tree
Location: Baron's Office
Added : December 20, 2003; December 20, 2006
Removed : Unknown; January 2, 2007
Proposal: Add December 14, remove January 2
Decor : Menorah
Location: Takotah Rooftop
Added : December 20,2003
Removed : Unknown
Proposal: Add/Remove on appropriate dates each year,
Proposal: Light candles at appropriate sunset times for New Mexico
Decor : New Year's Banner and Fireworks
Location: Neighborhoods
Added : December 30, 2006
Removed : January 2, 2007
Proposal: Add December 30, remove January 2
Decor : Winter in Delin
Location: Eder Delin
Added : February 20, 2007; March 8, 2008 (?)
Removed : April 5, 2007
Proposal: Add randomly mid-Feb to mid-March, remove mid-April to mid-May
Event : D'ni New Year - Leefo 1
Date : April 21, 2007
Event : First Feast of the Maker - Lenovoo 10
Date : March 27, 2007
Event : First Common Library of D'ni Opened - Leefo 12
Date : May 5, 2007
Event : Second Feast of the Maker - Leebro 20
Date : June 21, 2007
Event : The Day of Dancing - Leetar 21
Date : September 3, 2007
Event : First Arrival of the Great King - Leevot 12
Date : September 28, 2007
Event : Third Feast of the Maker, Leevofo 18
Date : November 11, 2007
Event : Coornation of King Kerath - Leevofo 27
Date : November 23, 2007
Event : Anniversary Lost Book of Birenni
Date : December 10, 2003
Event : D'ni Guild of Writers Founded - Leevot 9
Date :
Event : The Day of the Circle - Leenoovo 18
Date :
Event : Pento War Begins - Leevot 12
Date :
Event : Fall of D'ni - Leesahn 8
Date :
Flame : January Flame
Location: Gahreesen
Added : January 17, 2007; January 2, 2008
Removed : February 1, 2007
Proposal: Add January 1, remove February 1
Flame : February Flame
Location: Kadish Tolesa
Added : February 1, 2007
Removed : March 1, 2007
Proposal: Add February 1, remove March 1
Flame : March Flame
Location: Eder Gira
Added : March 1, 2007
Removed : April 2, 2007
Proposal: Add March 1, remove April 1
Flame : April Flame
Location: Gahreesen
Added : April 2, 2007
Removed : May 1, 2007
Proposal: Add April 1, remove May 1
Flame : May Flame
Location: Descent
Added : May 1, 2007
Removed : June 1, 2007
Proposal: Add May 1, remove June 1
Flame : June Flame
Location: Minkata
Added : June 1, 2007
Removed : July 2, 2007
Proposal: Add June 1, remove July 1
Flame : July Flame
Location: Gahreesen
Added : July 2, 2007
Removed : August 1, 2007
Proposal: Add July 1, remove August 1
Flame : August Flame
Location: Jalak Dador
Added : August 1, 2007
Removed : September 8, 2007
Proposal: Add August 1, remove September 1
Flame : September Flame
Location: Teledahn
Added : September 8, 2007
Removed : October 3, 2007
Proposal: Add September 1, remove October 1
Flame : October Flame
Location: Phil's Relto
Added : October 3, 2007
Removed : November 1, 2007
Proposal: Add October 1, remove November 1
Flame : November Flame
Location: Great Zero
Added : November 1, 2007
Removed : December 7, 2007
Proposal: Add November 1, remove December 1
Flame : December Flame
Location: Myst
Added : December 7, 2007
Removed : January 2, 2008
Proposal: Add December 1, remove January 1
Location: Kadish Tolesa
Added : December 20, 2006
Removed : Unknown (GoG claims "Still available")
Proposal: Make monthly random, 40% chance to appear
Clothing: First Month Shirt
Location: Great Stair, City
Added : December 21, 2006
Removed : February 1, 2007
Proposal: Make available 1st month per shard
Clothing: St. Patrick's Hat
Location: Closet
Added : March 7, 2007
Removed : Unknown (GoG claims "Still available")
Proposal: Make available for 21 days with St. Patrick's in the middle
Clothing: College Basketball Jersey Shirt
Location: Closet
Added : March 11, 2007
Removed : Unknown (GoG claims "Still available")
Proposal: Make available during normal March Madness week(s)
Clothing: Santa Hat
Location: Closet
Added : December 24, 2003; December 21, 2006
Removed : December 26, 2003; January 1, 2007
Proposal: Add December 14, remove w/ New Year (same as tree)
Decor : Fall Decorations
Location: Neighborhoods
Added : November 22, 2003; October 26, 2007
Removed : Unknown
Proposal: Add 1 week before Halloween, remove on Saturday after Thanksgiving
Decor : Christmas Tree
Location: Baron's Office
Added : December 20, 2003; December 20, 2006
Removed : Unknown; January 2, 2007
Proposal: Add December 14, remove January 2
Decor : Menorah
Location: Takotah Rooftop
Added : December 20,2003
Removed : Unknown
Proposal: Add/Remove on appropriate dates each year,
Proposal: Light candles at appropriate sunset times for New Mexico
Decor : New Year's Banner and Fireworks
Location: Neighborhoods
Added : December 30, 2006
Removed : January 2, 2007
Proposal: Add December 30, remove January 2
Decor : Winter in Delin
Location: Eder Delin
Added : February 20, 2007; March 8, 2008 (?)
Removed : April 5, 2007
Proposal: Add randomly mid-Feb to mid-March, remove mid-April to mid-May
Event : D'ni New Year - Leefo 1
Date : April 21, 2007
Event : First Feast of the Maker - Lenovoo 10
Date : March 27, 2007
Event : First Common Library of D'ni Opened - Leefo 12
Date : May 5, 2007
Event : Second Feast of the Maker - Leebro 20
Date : June 21, 2007
Event : The Day of Dancing - Leetar 21
Date : September 3, 2007
Event : First Arrival of the Great King - Leevot 12
Date : September 28, 2007
Event : Third Feast of the Maker, Leevofo 18
Date : November 11, 2007
Event : Coornation of King Kerath - Leevofo 27
Date : November 23, 2007
Event : Anniversary Lost Book of Birenni
Date : December 10, 2003
Event : D'ni Guild of Writers Founded - Leevot 9
Date :
Event : The Day of the Circle - Leenoovo 18
Date :
Event : Pento War Begins - Leevot 12
Date :
Event : Fall of D'ni - Leesahn 8
Date :
Flame : January Flame
Location: Gahreesen
Added : January 17, 2007; January 2, 2008
Removed : February 1, 2007
Proposal: Add January 1, remove February 1
Flame : February Flame
Location: Kadish Tolesa
Added : February 1, 2007
Removed : March 1, 2007
Proposal: Add February 1, remove March 1
Flame : March Flame
Location: Eder Gira
Added : March 1, 2007
Removed : April 2, 2007
Proposal: Add March 1, remove April 1
Flame : April Flame
Location: Gahreesen
Added : April 2, 2007
Removed : May 1, 2007
Proposal: Add April 1, remove May 1
Flame : May Flame
Location: Descent
Added : May 1, 2007
Removed : June 1, 2007
Proposal: Add May 1, remove June 1
Flame : June Flame
Location: Minkata
Added : June 1, 2007
Removed : July 2, 2007
Proposal: Add June 1, remove July 1
Flame : July Flame
Location: Gahreesen
Added : July 2, 2007
Removed : August 1, 2007
Proposal: Add July 1, remove August 1
Flame : August Flame
Location: Jalak Dador
Added : August 1, 2007
Removed : September 8, 2007
Proposal: Add August 1, remove September 1
Flame : September Flame
Location: Teledahn
Added : September 8, 2007
Removed : October 3, 2007
Proposal: Add September 1, remove October 1
Flame : October Flame
Location: Phil's Relto
Added : October 3, 2007
Removed : November 1, 2007
Proposal: Add October 1, remove November 1
Flame : November Flame
Location: Great Zero
Added : November 1, 2007
Removed : December 7, 2007
Proposal: Add November 1, remove December 1
Flame : December Flame
Location: Myst
Added : December 7, 2007
Removed : January 2, 2008
Proposal: Add December 1, remove January 1