The Vent plugin allows you to use the WordPress Scheduled posts functionality to enter,list and manage events.
The Vent events system allows you to use the standard WordPress scheduled posts functionality to enter, list and manage future events.
The administrator can setup the criteria that the Vent system uses to identify an Event. This enables you to continue to enter scheduled posts into WordPress (and more importantly, for them to function exactly as before) whilst still using the new Event functionality.
The simplest of criteria is to mark any events with a distinct category or tag, alternatively you can use any combination of the settings shown above, including looking for a string at the start of a post title (such as "Event:").