Hi Richard,
This scenario can be accomplished using a qSelector and a qListView.
In the qSelector you display the events and in the qListView the Tasks.
You need to set the qSelector to refresh the page when selection change and set a session variable that will be passed to the qListView in a CAML filter condition. In this when when the user selects an event, the session variable will be set, the page refreshes and the CAML filter would filter the Tasks and displays the tasks for the event selected.