Nothing too special here. Just a screen that tells subjects that they can take a break. Asks them to type the word "go" in password field when they are ready to continue. I use it for longer experiments in which I want minimal subject/experimenter contact (i.e, subjects don't need to interact with experimenter using this method).
Obviously, you'll want to change the wording of the screen to match your needs. Of course, the password can be changed also.