When you sleep, your soul briefly returns to the place where it was created/goes to when it dies, and seeks nourishment. Everybody's soul is created with a little link (or you could say a greater entity calls it back) to that place so that it can return easily, but upon death, the soul returns via that and annihilates the link as if returns.
Also, as an added thingy, you could say the entity supplying the link, or residue of the links themselves, (whichever) is the source of all arcane power.
Marraige custom. The groom must prove his worth to the friends, family, and future wife. The best man is obligated to challenge the groom to a duel and the best man chooses the weapons. (can be anything, toothpicks, cotton balls, anything) If the groom wins then he proves his worth. If he loses then the bride will accept him for his faults and could sometimes gives him a task to accomplish before the wedding.
Facial tattoos in various designs are a sign of status in some cultures.
Legends abound in some places about ancient landforms (Islands, Peninsulas, Mountains) that dissapeared long ago in towers of glowing energy. (See Any Unnatainable Glory entries for more info)
A culture believes that souls are recycled. One child gets half of a soul, another child gets the other half. However, this means that with each passing generation, the amount of soul in the child will become less and less (Through division)until their culture will die in the future because of their soulless offspring.
A cave with weapons sunken into the walls, blades sticking out of the floor and ceiling, and so on. Possibly, any weapon used in it could be torn out of the hand and sink into the stone.
A low lying area will flood after rains causing many people to be stranded and many roads are covered with water and unuseable.
Religious city. Hundreds of vendors selling small statues which sole value is as a donation to one of the many gods that are worshipped.
Minor Cultural Modifier: The culture believes, for the soul to leave the body, the corpse' eyes must be open. So any member of that culture takes care any dead body they find has its eyes open. Doubly true for those they kill themselves, for then the corpse will surely rise as an undead hunting him.
In cases where a person has accused another of a crime, but there are no other supporters of the accusation or defenders of the accused, and there is not enough evidence to support one party or the other, the two people involved, or their champions in some cases, must duel in the presence of the local ruler or leader. The loser is assumed to be lying and punished accordingly.
There is an important pair of fraternal twins. Possibly minor dieties, sorcerers, or maybe just an important pair of nobles. One is evil and one is good. The thing is, the one who looks evil at first glance is the good one, and vice versa.
There is a group that believes no good can come of trying to change to future to render a prophecy or prediction incorrect. They believe that meddling will either cause the prediction to be true in the first place, or make something worse or more extreme happen.
There is a person who has a well-known reputation, probably involving something illegal. But this person is either very clever and crafty, or really like his or her privacy, for no one knows who this person actually is. As an added twist, perhaps this person is of an age that would noramlly be wildly inappropriate (say, a child is a much-feared bandit) or maybe not the expected gender or even race.
Other improvisational weapons/tools:
Icicles are useful as daggers,
Bag Of Holding filled with copper pieces used by chucking the contents at foes, (by strolen)
sleeves make useful garrotes. Ya can't cut anyone's neck, but you sure can choke 'em!
Flaming Logs make great clubs, (any Barbarians out there?)
and Bee hives are very effective when thrown at a mob of enemies. :-)
The Chinese, when attacking a castle or fort, flew kites over the city wall and used the length of string it took to get it there as a measurement to know how far they had to dig a tunnel to get under the wall.
A culture has a tradition of wearing animal pelts as a sign of status or job. Carpenters might wear beaver skins, Masons have a moleskin hood to their cloak, Gaurdsmen might have badger pelts. Done to show the culture's respect for nature and how much of nature is equal to each other.
Termites, in certain places, make homes that can be eight meters high and only a half meter wide. They are built facing North to South to take advantages of the suns travel, maximum heat in the morning and evening and little in the afternoon. Imagine grassy plains with vertical structions facing a certain direction all over the place. Ambush? Maze? New creature? Larger structures?
Silk Armor? The Mongols wore silk undergarments under layers of leather armor. Why? Because silk is very strong. If an arrow hit them and made it through their armor, it would usually not have enough energy to puncture the silk. It could still enter their body but, because the silk would not break, the arrow's barbs could not do their work and the arrow could easily be removed leaving a relatively clean wound considering normal arrow wounds.
Perhaps divinations, if strong enough, can actually change the future, instead of predicting it.
A possible answer to what happens to spells when a mage dies. If the spell is strong enough, say and enchantment or other permenant effect, part of the mages spirit may become lodged in the magic. It may be a way for items to gain some kind of intelligence, but a mage who has knowledge of this fact would be very hesitant about enchanting anyone or thing. He might have other plans for his afterlife than counting the change in your bag of holding.
Preists, I think, would have this sort of thing covered.
If it was a castle, it was the strangest one he had ever seen.
He of course saw the main tower - taller than anything he had seen outside of Stoneholt, the spire looked fragile and was topped by a glassed-in chamber.
The outer wall was so gently sloped that it would have only stopped a horde of hobbling old men, an able-bodied soldier could stride up to its crest with little effort. Within one saw a huge, nearly perfect bowl-shaped area with the base of the tower in the centre, covered in hundreds of mirrors.
This structure is a massive solar collector designed by the Wizard-King Aardwal in centuries past. He used the concentrated light in his investigations into the magic of light, and in the fashioning of flash crystals.