Event-based systems are increasingly gaining widespread attention for applications that require integration with loosely coupled and distributed systems for time-critical business solutions. In this paper, we show concepts and models for representing, structuring and typing events. We discuss existing event models in the field and introduce the event model of the event-based system SARI for illustrating various typing concepts. The typing concepts cover topics such as type inheritance and exheritance, dynamic type inferencing, attribute types, as well as the extendibility and addressability of events. We show how the typing concepts evolved and depend on the implemented event-based systems which use different approaches for the event processing such as graphical approaches, or approaches, that use Java code, SQL code, or ECA (event-condition-action) rules.