Wiktionary
n. (context informal English) A board held off camera during a live television broadcast to prompt the presenter.
Usage examples of "idiot board".
Glancing round at the idiot board to find out what question he was supposed to ask her first, he saw chalked in large letters: 'James Vereker can't do his programme without having a bonk first'.
Sarah, who had also seen the idiot board, screamed with laughter, and it was thus that the viewers had their first glimpse of her.
The chance of making a fatal error had been greatly reduced by the provision of an 'idiot board' - an abbreviated list covering the essential control checks and settings a pilot was required to implement on take-off and landing.
Kelso gunned the motor and ran quickly through the take-off checks as Jodi read them off the idiot board.