Most studies take for granted the critical first steps that prelude interaction with a public display: awareness of the interactive affordances of the display, and enticement to interact. In this paper we investigate mechanisms for enticing interaction on public displays, and study the effectiveness of visual signals in overcoming the 'first click' problem. We combined 3 atomic visual elements (color/greyscale, animation/static, and icon/text) to form 8 visual signals that were deployed on 8 interactive public displays on a university campus for 8 days. Our findings show that text is more effective in enticing interaction than icons, color more than greyscale, and static signals are more effective than animated. Further, we identify gender differences in the effectiveness of these signals. Finally, we identify a behavior termed "display avoidance" that people exhibit with interactive public displays.