During term, the G30 MCS will be used for courses between 1300 and 1730 every weekday. There is no access to the MCS for any other purpose during these times without the express permission of the course demonstrator; if you harass demonstrators for such permission or enter without permission, your MCS account may be cancelled.
If you are on a course, you should not consider this a definitive list of course times.
The MCS is normally open between circa 0830 and 2000, but you should not rely on it being open after 1800. It is sometimes open at weekends, and the security guard should be willing to open it at your request.