Games where the time affects gameplay?

[Flake]

I am trying to get together a list of games where the time affects the gameplay, be it the time of day or the year or the month...

I know NiGHTS and Animal Crossing do this. What are some other significant titles with this kind of gameplay convention?

EDIT: The list so far as provided by you kindly folks

Animal Crossing Series
Boktai
Mana Khemia
NiGHTS series
Nier
Pokemon Series

[AppleQueso]

you should probably clarify whether you want examples of games with time travel plots.

[Gooseberrysoda]

Pokemon G/S/C do, if you get the Pokerus. Too bad that almost never happens.

[Flake]

you should probably clarify whether you want examples of games with time travel plots.

I am talking about gameplay conventions, not plot. I am curious about games where an internal clock or some other manner of determining 'when' it is affects the gameplay to include changes in game presentation, changes in actual gameplay, changes in difficulty, etc.

[noiseredux]

not a "clock" but I feel inclined to mention Boktai with it's solar sensor determining how many vampires will be out and about.

[Anapan]

Mana Khemia on PS2 has a clock that affects what enemies are around (sometimes), how tough they are (night time makes everything much harder), and which items you can find/farm/mine/catch. The plot is advanced by time as well. I think the other games in the series have the same game play gimmick.

[YoshiEgg25]

Pokemon Gold/Silver/Crystal (GBC), Diamond/Pearl/Platinum (DS), and HeartGold/SoulSilver (DS) have different Pokemon depending on the time of day, have different Pokemon depending on what day it is, and G/S/C/HG/SS have certain people appear that give you gifts depending on the day.

Along with Animal Crossing (GCN), don't forget Animal Crossing: Wild World (DS) and Animal Crossing: City Folk (Wii).

[Czernobog]

Nier on PS3 that has an internal clock which definitely affects some of the side quests like......gardening.......and.....fishing maybe.

[MrHealthy]

Pokemon G/S/C do, if you get the Pokerus. Too bad that almost never happens.

Ummm, time of day / day of week also affects wild pokemon battles, and certian trainer battles and NPC locations.

This is true for all latter hand held pokemon games too. So R/S/E on GBA (to a lesser extent), D/P/Pt on DS, HG/SS on DS and B/W on DS.

[Gamerforlife]

Sort of obscure, but I remember a Dynasty Warriors game where you could decide the kinds of bodyguards the game would generate for you by playing around with the clock or date on your system

There's a quest in Castlevania: Portrait of Ruin that can only be completed when the little hand on your DS clock is on 12