A friend of mine out at Simon Fraser University informed me that Google Calendar is very big there and that a lot of student groups and the University post to Google Calendar so that others can import their events into their personal calendars. I decided to see what is out there at McMaster.
I found four McMaster Community Calendars. (click the icons to download them in the listed format)
This one list important dates from the Undergraduate Calendar: 
The IRC has a calendar available of all their events:
The MBA Association:
The McMaster Catholic Students’ Association:
Guaranteed that I missed one somewhere… add it to the comments and I will add it to the post.