monday
From 8pm until midnight on a Saturday night.
Animal Crossing City Folk will never come out for the DS, DS lite, or DSi - it is strictly for the Wii console.
Maybe. It comes out late at night on coconut trees in the summer.
There is: Animal Crossing: City Folk [Wii] Animal Crossing: Let's Go To The City [FOR EUROPE] [Wii] Animal Crossing: Wild World [DS] Animal Crossing [Gamecube] Animal Forest [+E64, probably gamecube.] Animal Crossing: 3DS [Will come out in 2012] [3DS]
Thanksgiving
no no
Ocean Sunfish come to the Sea in the summer. And, its not a big problem, but the true name is actually Animal Crossing City Folk, not Animal Crossing Lets go To the City.
Scorpions come out July-September at night.
yes
Halloween
It comes at night. You need to have a slingshot to shoot it out of the sky.
Random days.