OK, about 2 weeks ago my high school had it's annual variety show. I was the sound designer and operator. There was one big act in which all of choirs were involved (over 150 people) . For the act we were a projector that played a video that set up the scene for the dance act. Just a note: Our light guys are lazy asses that screw around when they should be working. Before the show i said " Lights everything ready?" they said Yup yup. So the Emcees are on stage announcing the next act(which was the dance act). I go on headset and tell the light guy to cue up the video. Then the Emcees finished and i said play video. I brought up sound and he pressed play but....the lazy ass light guys forgot to turn the projector on. So we were going nuts on headset trying to tell all the dance act that there is no video. .... Everyone was a little ticked since turning on the projector was all the light guy had to do. But everything worked out and people caught on fast and turned out to be our best show.