I am a salareid employee working for a non-profit and my work week is Monday - Friday. We have a special week long event coming up that we are now required to work at and one of the days I'm reqired to work is on a Saturday which I normally have off. They are only compensating me half a day. Is there anything I can do?

As a salaried employee you are not paid by the hour, so officially there is no recourse. I am surprised that they are compensating you for half a day, as most employers wouldn't do that.