[Evolution] calendar icons

[shivers mongkok dyndns org (Olin Shivers)]

I am trying to use evolution for calendaring. I'm accessing some
calendars via CalDAV. My appointments show up in the month view with
a bewildering set of icons associated with each appt. None of them appear
in the documentation, which is pretty annoying -- not much point in providing
a colorful icon if its purpose is unexplained. It makes the display *less*
informative and more cluttered.

Some of these icons I can puzzle out: 
- the little bell means an alarm has been set. 
- The pair of blue arrows going in a circle mean "recurring event."

But there are two that resist analysis:
- A pair of people, head-and-shoulders.
- A yellow thumbtack in a green square.

Can someone tell me what these things are?
    -Olin