Open/Closed

Is there a way or plugin to show that a business is open or closed to display on the site that would allow a customer/user to know what our hours are? We are a new business and rely on volunteers that are not able to have the space open at regular hours and we would like to have a way to show when we are open. Ideally we would have the volunteer login and push a radio button on the wordpress site when we open and deselect it when we close.

Thanks