A computer system that communicates with information indicative of a lighting show, and provides information to users in the audience to allow their phones to be interactive with the show. In one embodiment a lighting designer or show promoter can provide information R that extends the lighting effect on to the user's phone. In another embodiment, the show promoter may provide information indicative of the venue. The information can be location specific, for example information that is provided to a specific client device can be based on the specific location of the client device. This can provide location sensitive lighting information, or maps, or in seat specific information about the venue.