Вот очень базовая реализация формата ICS. Он предназначен для доступа через браузер, но было бы довольно академично изменить текстовый файл с расширением ICS и отправить его по электронной почте.
<cfheader name="Content-Disposition" value="attachment; filename=event.ics" />
<cfcontent reset="true" type="text/calendar" />
<cfscript>
// handle all-day events
if (NOT isDate(starttime) OR NOT isDate(endtime)) {
dtstart=';VALUE=DATE:#dateFormat(eventdate,"yyyymmdd")#';
dtend=';VALUE=DATE:#dateFormat(dateAdd("d",1,eventdate),"yyyymmdd")#';
} else {
dtstart=';TZID="Eastern Standard Time":#dateFormat(eventdate,"yyyymmdd")#T#timeFormat(starttime,"HHmmss")#';
dtend=';TZID="Eastern Standard Time":#dateFormat(eventdate,"yyyymmdd")#T#timeFormat(endtime,"HHmmss")#';
}
</cfscript>
<cfoutput>
BEGIN:VCALENDAR
PRODID:-//Company//Source//EN
VERSION:2.0
METHOD:PUBLISH
BEGIN:VTIMEZONE
TZID:Eastern Standard Time
BEGIN:STANDARD
DTSTART:16011104T020000
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:16010311T020000
RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
END:DAYLIGHT
END:VTIMEZONE
BEGIN:VEVENT
CLASS:PUBLIC
CREATED:#dateFormat(dateAdded,"yyyymmdd")#T#timeFormat(dateAdded,"HHmmss")#Z
DESCRIPTION:#desc#
DTEND#dtend#
DTSTAMP:#dateFormat(dateAdded,"yyyymmdd")#T#timeFormat(dateAdded,"HHmmss")#Z
DTSTART#dtstart#
LAST-MODIFIED:#dateFormat(dateApproved,"yyyymmdd")#T#timeFormat(dateApproved,"HHmmss")#Z
LOCATION:#location#
PRIORITY:5
SEQUENCE:0
SUMMARY;LANGUAGE=en-us:#title#
TRANSP:OPAQUE
UID:#dateFormat(now(),"yyyymmdd")#T#timeFormat(now(),"HHmmss")#Z@#uniqueID#
BEGIN:VALARM
TRIGGER:-PT15M
ACTION:DISPLAY
DESCRIPTION:Reminder
END:VALARM
END:VEVENT
END:VCALENDAR
</cfoutput>