I like the coin idea. I collect military patches, and all of mine have been given to me by friends or acquaintances, or are from units I served with; there is a name and story for each patch. To have coins from here and the Aerodrome would have a similar feel - a community token.

I haven't heard these referred to as challenge coins, so at first I thought they had something to do with dueling. What is the history behind the term challenge?