It is an often asked question. It usually ends up talking about a Chinese tomb that may have a lot of mercury in suspension in the air. If I recall correctly, some skeletons of presumed tomb robbers have been found inside some egyptian tombs.

http://www.reddit.com/r/AskHistorians/search?q=traps&restrict_sr=on&sort=relevance&t=all

There is a story of this sort in the work of the Byzantine historian Zonaras (probably based on an earlier source, but I don't know which). King Herod ( of "kill all the babies" fame) had heard that his predecessor, King Hyrcanus, had opened the tomb of David and found there 3000 talents of silver. Wanting some of that for himself, he gathered a few loyal henchmen and entered the tomb secretly. No money was left, but they did find plenty of gold ornaments; being greedy,however, he kept pushing further until they reached the innermost chamber where they found the sarcophagi of David and Solomon. Two of the henchmen tried to open them, but flames sprouted from inside and burned them to a crisp. Herod hightailed it out of there and never looked back.

I've been reading "playing at the world" by Jon Peterson, and he makes the point that the "dungeons" in D&D were originally intended to indicate where sappers (siege engineer tunnelers) might connect to a defended position's lower levels during table-top war games. I think the modern concept of a "dungeon" has more to do with a happy accident and the availability of graph paper than it does with historical precedent.

Invading via tunnels would certainly involve armed teams, but traps/treasure seem unlikely to me.

It's also worth pointing out that Egyptian tombs and central/south american temples were products of the engineering of their time. Despite their (often massive) external size, they weren't really built to have much internal space (there just isn't much to explore in there). The same issue applies to later period fortified structures as well- thick, defensive walls means the space inside is a precious commodity.

Someone here mentioned the [Money Pit,] (http://en.wikipedia.org/wiki/Oak_Island#History_of_the_Money_Pit) I thought that was an informative and interesting question! Thank you, whoever you were.

It's a common motif in the sagas, actually. Hero has an awesome sword, dies, is buried with it, and a few generations later, a new hero comes to claim the weapon. To do this, though, the hero needs to open the burial mound and contest again a draugr or other supernatural creature, usually the original hero!

You see this happening in sagas like Grettis saga or Hervors saga.

When I'm not on mobile, I'll see if I can link the relevant sections.