OK, I've had a look at this now. There is an application event for reminders which I just used by adding a new task with the subject: "TEST" and setting a reminder.

In the VBE, select 'Application' in the object dropdown and 'Reminder' from the events and add this code
[VBA]Private Sub Application_Reminder(ByVal Item As Object)

If Item.Subject = "TEST" Then MsgBox "The Application_Reminder event just fired."

End Sub
[/VBA]
This worked nicely, so you'll be able to set a recurring task that fires you code at a regular time each day/week/month or have the option of setting one up whenever you like - any reminder will fire the code if it's item's subject value matches

Enjoy :-)