Munich standardizes on Kolab for its groupware
If you've been following the trials and tribulations of German city Munich's transition from Windows to Linux, you know they've moved 15,500 desktops onto Linux. They've now taken the next step and selected a standardized groupware solution for communication: Kolab. What, you were expecting Exchange Server?
More realistically, they might've stuck with a Windows Echange server, but used a compatible Linux client on the desktop(s). Assuming they didn't just make do with sendmail and Thunderbird, and some Unixy calender application (cron?).