I like to translate scenes from life and art into gaming mechanics. This helps me visualize the interface between game and story.
For example, yesterday was a particularly cold day in Seattle. By early afternoon, the sun was shining, the temperature was above freezing, and the ice was mostly melted. As my wife and I left for the store, I made a comment about the possibility of black ice.
About three minutes later, we were chatting about home owners associations and some new homes for sale on our block and had forgotten all about the potential for black ice. As we crossed the street, we transitioned from a sunny spot, to a shady spot. Our feet hit the shade and we simultaneously slipped on the black ice. I managed to catch myself without too much strain, my wife twisted her hip a bit, fell on one knee, but avoided serious injury.
What just happened?
In Dungeons and Dragons 4th edition terms, we weren’t actively looking for trouble. Whatever perception check we used was penalized, and we both failed. That hazard attacked reflex; I tend to be a lighter on my feet than she, so my defense was higher. The attack value the hazard rolled hit her for a few hit points of damage (noted by the sore knee and hip), but missed me. Note that I had to exert some energy to catch myself, just as you might imagine 4e player characters doing to avoid an attack.
I’m just glad that ice trap didn’t roll a natural 20.