I've created ICS files from a few events, but they won't import into either Google Calendar or the calendar extension I use for Thunderbird.
I took a look at the contents of the files, and in the line after the "contact" field, there appears to be a bunch of HTML (begins with "
It was also missing an "END:VEVENT" and an "END:VCALENDAR"
Once I killed out the html and added those, the file imported just fine.