The Open Tasks Tab lets you view all open Tasks with references to Salesforce Objects (Account, Lead, Opportunity, ..) or custom objects.
Also check the Task Management options.
You can restrict the query to specific Task Status values (e.g. Not Started) or certain Users.
Select multiple values by pressing the SHIFT button
or de-select a value by pressing the Win or Cmd (Mac) Button while clicking on the selection.
Clicking on the button Query (reset to all open) will reset the query options to open Tasks for all Objects and users created by a checklist.
Refresh Options updates the various options and their count.
Task Query Summary
View the totals by Status, Object, Assigned To and Record.
For each record, view the total of open and closed tasks.
View the details when Show Task Details is selected in the query.