I hope they'd have some kind calendar events like the one from Rune Factory. Festivals and stuff. Imagine during Chinese new year in-game and they'd have lanterns around town and have some special minigames with prizes you can get only during that day. The NPCs would also dress differently. Fireworks on thanksgiving, some special event on your designated birthday. Random cutscenes anytime of the year. Plus, special dating cutscenes cutscenes during events.
How about you? What events/festivals can you imagine in the game?
EDIT: Halloween too!