Dungeon Crawl/Traps issues...

[Ogrork the Mighty]

I'd be more likely to put up a riddle that guarenteed death.

The only correct answer being not to answer at all...

 

[Evilhalfling]

I tend to place mostly magical traps of the doing x sets of y spell - unless you have the password. Honestly traps by the rules are expensive, and all those complicated mechanisms will probably jam.
My last dungeon had a helpful clue carved in the wall, below it was carved -
dont't try it.
The first clue was put in by the creator, designed to set off multiple traps, when left to themselves vistors would only have set of 1 or two before wiseing up. I haven't done a lair made by engineers, who actually might throw in some complex traps.