Attached calendar in notification email displayed as plain text if not supported

[fbouquet]

My email reader (Thunderbird) seems like it doesn't support ICS calendar attachments and it displays it as plain text at the top of notification emails, which would make me flew if I didn't know where it comes from.
I guess there's a way to kind of comment it in case it isn't supported, like IE hacks for a website, I'll try to get it done.
Here is the type of ugly jam I get at the top of my emails:

"BEGIN:VCALENDAR
VERSION:2.0
PRODID:icalendar-ruby
CALSCALE:GREGORIAN
METHOD:REQUEST
BEGIN:VEVENT
DTSTAMP:20140729T210417Z
UID:http://www.railsschool.org/l/beginner-class-with-ruby-on-rails
DTSTART:20140730T173000
DTEND:20140730T193000
CLASS:PUBLIC
CREATED:20140720T200420
DESCRIPTION:Hands on and action-packed!
LAST-MODIFIED:20140729T170414
LOCATION:Coshx Labs - 1110 E. Market St. N7, Charlottesville, Virginia,
United States, 22902
SUMMARY:Beginner Class with Ruby on Rails
URL:http://www.railsschool.org/l/beginner-class-with-ruby-on-rails
END:VEVENT
END:VCALENDAR"