Where do I get my card so I can tell my teachers why I won't speak on the national day of silence?

The national day of silence is for gay rights and I will need a card that I can show to my teachers on that day so that I can continue with my silence. I was told that there is a site where I could get a card to show them. Does anyone know what that site is? Thank you so much!|||http://www.tysonrainbow.com/Day-of-Silence.html