People jumping out at people are always the best way to go, cheap, and really effective if you get the right people. I built a hauted house last year for a church, and i worked in it to, we had scary sounds, and the usual axes and stuff. But the reason it was great it we had about ten people hidden throughout it, scaring the crap out of people. I was just in all black robes with some nasty mask being a creep in a dark corner, and id alternate jumping out and grabbing people and just walking out slowly behing them and following them..id follow them for a bit then reach out and grab their shoulder and they would start screaming and running and stuff, I actually made a few people cry. A giant creep following you in a dark ally FTW!