<p>You work there and you didn't know? </p>
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<p>I'd be upset enough to go to the person in charge and tell them that there needs to be a monthly calendar arranged. Whoever arranges special events like that needs to be on the ball about contacting whoever manages the calendar.</p>
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<p>At a minimum, the calendar should be posted to the main entrances of the school and be in an easy to access place in the office (e.g. on the reception counter if there is one), ideally it'd also be on the school's website, and made available via a voluntary email list. Ideally, too, the school would have a policy that if it isn't on the calendar at least 2 weeks before, it doesn't happen.</p>