I have my own (earned) challenge coin now.

It is from the ASP instructor course (telescopic baton). By far not as nice as a SOG coin though. I had my agent number engraved in it.
Since only three guys in my plt did the course there isnīt much fun doing a coin challenge.

However, I learned a lot there, and as a plus one of the instructors was ex-GIGN (French CT unit) wich was kinda cool. On the downside, we got a demo on the Taser. That was no fun at all.It hurts a lot.