Some nonprofit boards have seats assigned to ex officio members. According to a number of sources, an ex officio (often times a government official and often an official who reprents a money-path) is assigned a seat "because of the position they hold". The bylaws define whether this representative has a vote but ex officio status and voting rights are not implied by the title.
The Penn State situation reminds us though that an ex officio has the potential to wield significant authority. The Governor of Pennsylvania holds an ex officio position on the Penn State board. While he rarely attends meetings (not something I'm particularly fond of) he likely sends a representative on his behalf just to keep his ears to the ground. As the New York Times article on this matter points out, the Governor had a great interest in this situation at Penn State and wanted to ensure the best results. The Governor exercised his authority and rights as an ex officio member of the board and in my opinion, for the right reasons and results.
Thanks Claire and thanks Penn State for affording us all one more lesson in governance.