Hidden Cave:
Once you have the Sword of Legend from the princess and got to the 255th floor of the Middle Class Mines, you may enter the cave behind the waterfall. Equip the sword and examine either rock by the waterfall.

Possible Brides:
The girls you can marry include the Harvest Goddess, the Harvest Witch, the Princess, Keria, Leia, Flora, Muffy, Nami, Lumina, Celia, Ann, Popuri, Elli, Karen, and Mary. If you marry the Goddess or the Witch, you have a chance to have a special child that dresses funny.

Littering:
The only place you can safely litter is on your own field. Littering anywhere else (including other fields in town) will cause people to get angry with you. It can totally blow your chances with the ladies as well, so either stick it in your backpack or litter properly. Weeds count as litter too!