You can find out what time slots are available and what time works best for you if you take a look at the sign up shifts list. Go ahead and register so you can get free entry as a student (your name needs to be on the list). Here's the link to register if you didn't see the previous forwarded message I received from them:
http://usgbc-ie.org/upcoming/featured/ In order to get the free membership you will have to dedicate at least 2 hours of volunteer time. So far I have Rose, Joe, Sami and I. Anyone else interested? :)