We had a long hall at the beginning of our show that brought the guests from the street front where the line, etc were to the back of the building where the show really started. This was always an issue for us.
The cheap and easy solution was a lazer vortex tunnel. A few fog machines and about $10 in parts and we were set. The cool part was actors could be on one side of the laser effect and not be seen by the guests coming down the hall, but the actors could easily see the guests. They could get right up to the guests and then appear. On top of that the effect created a great distraction because it really is cool to see. Actors could hide in the dark and let the guests just walk right by and get them from behind.
It had to be one of the best bang for the buck effect and solved a difficult area.
Mid State Scare - San Luis Obispo and Santa Maria's favorite Haunted House
2013 - Hmmm, we shall see what gets conjured up