Classtag is a website and app for organizing parents and teachers.  Classrooms use ClassTag to manage activities, volunteers and reminders so you can spend time teaching.  The main features are:

1.  Connect the parents and children to faces and names, enabling parent-to-parent collaboration on a safe and secure platform. 
2.  Organize required and voluntary activities. See who is coming and who hasn't yet replied. Calendar integration and really smart automated reminders means one less thing to worry about.
3.  Streamline your communication with automated updates and reminders for important calendar dates. Know who has read your announcements about homework, assessments and other key items.