I have made a little python module (html color-coded) to OpenGroupware, to simplify appointment notifications. Used a lot.

appsObj = Appointments()
appsObj.connect(user,password)
appsObj.fetch(start,end)
for appObj in appsObj.Appointments:
    print appObj.startPretty, appObj.endPretty, appObj.title
    for participant in appObj.participants:
        print "\t", participant.name

There is a usage example in the module:

eliphas$ python ogoObjects.py
Username: eliphas
Password: ***

Schedule:

Today, 13:30 - Today, 15:45: Reunião com Luís Cláudio
        Eliphas Theodoro
        João
Monday, 14:00 - Monday, 15:00: Dentista
        Eliphas Theodoro
eliphas$