I usually have a cheap monk costume, but my main act is our entranceway. Every year I fill it with back streamers, so everyone has to wade through essentially pitch black to get to the door. I usually start tapering off at waist height to not scare the little kids as much though, but it does terrify the parents and teenage friends a bit. This year I got a fog machine.
This is from 2010. it's not as dense as I like to go because I took to long to get the streamers and the dollar stores ran out.