My searching led me to this page which gave some code for parsing an RSS feed into a compatible ICS file. After some heavy modifications I was able to set up an iCalendar file I could subscribe to. I used an online iCalendar validator to make sure everything worked when I finished.

Hope this might be useful to someone else until NC State decides to publish their own ICS file.

Update: For those interested in keeping track of the mathematics department at NC State, I used the PHP Simple HTML DOM Parser to generate their calendar as an ICS file that you may subscribe to. It simply scrapes the data from the mathematics calendar.