(Times are in EST. Note this may be a bit outdated.)
@Not Lime Animator - 10am to 6am
@PolyDev - 5pm to 9am (if unavailable, it's because studying for exams or have class going on), 9:30pm to 8am (weekends)
@Absolute King 01 (on break currently) - 8am to 12pm, 1pm to 3pm (Monday to Friday); 2pm to 3pm (Saturday and Sunday)
@Hiandrew (retiring) - 7am to 11pm (weekdays)
I heard some people here complaining why some of the admins don't intervene immediately when they are pinged. It's because we're asleep or other matters that are not our control (like school). In this case, ping another admin if one doesn't work.