An ongoing timeline written by AK47Productions which is exactly what it says in the tin, with The Race from Harry Turtledove's Worldwar series invading two years later due to a computer problem that needed to be fixed aboard the 127th Emperor Hetto.
The discussion thread is here while the story only thread is here.
Part VII - Yesterday's Neutral is Today's New Ally
Part VIII - Somethings Old and Something New
Part XI - Coming Back to Save The Day
Part XV - "Run or Shoot? Both."
Part XVI - Gifts for the Masses
Part VIII - Through Canada to an American City
Declassified Document - Operation Hornet's Nest
Part XIX - Through Canada to an American City II
Part XXI - "...a war more total and radical than anything that we can even imagine today?"
Part XXII - War never changes. Not even with Aliens apparently.
Part XXIII - Fried Lizards, Fanatics, and other Fine Tosevite Forms of Fighting.
Part XXIV - "I aim at the stars, but sometimes I hit The Race."
Part XXV - Monster Here, Monsters There
Part XXVI - Diplomacy: Never Letting a Crisis Going to Waste.
Part XXVII - A Modern Day Siege
Part XXVIII - The Scramble for Earth.
Part XXXI - Another Day, Another Front
Part XXXII - Failure to Launch
Part XXXIII - Not Very Effective
Part XXXIV - Moving up in the World
Part XXXV - Backroom Deals and Backroom Thoughts
Part XXXVII - A Poisonous Touch
Revised map of original landings along with new landings from the Part IV update
Conquered territories of The Race as of the Part IV update
Conquered territories of The Race as of the Part VI update
Conquered territories of The Race as of the Part XXXI update