A few of my users found that the default printing of the tasks and calendar kind of sucked and requested something simple, one line per entry(they like to cross stuff off, lol), so I made them the attached using the icalcreator class from iCalcreator , the zimbra ics support and a little php. Of course such a report is not limited to zimbra, any ics source should work.
example out put included as pdf.
Hope that helps someone.
Maybe someday will make into a proper zimlet with config options and a button