The silent box is an
imaginary box.
this box is preferably funny with someone who is high on some sort of drug.
here's how it goes.
you find someone whos high or whatever,
and you say "this is the silent box" and then you make an
imaginary box with your fingers.
after they clearly see that this is the silent box, you go "okay your in the silent box now" and pretend to place this invisble box over their heads.
then you back up and start mouthing words, giving
the illusion that they are in a mute box and they cant hear you and you cant hear them.
you can do this as long as they fall for it, and i promise its so weird and so funny.
but i advise you, never go in the silent box. it will make you trip balls