SpamAssassin - Use this program to "Unspam" your mailbox(es).
Google Calendar - Spend less time managing your day & more time enjoying it
MailScanner - MailScanner is a open source email security system design for Linux-based email gateways.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Rspamd - Rspamd is an advanced spam filtering system that allows evaluation of messages by a number of rules...
iCal - In Calendar on your Mac, subscribe to calendars published or shared by others.