The open source hardware cast of characters

For those just tuning in, I pulled together a little play called Open Source Hardware, Vol 1. If my English teacher taught me anything from those paperback copies of Shakespeare (you know, the ones with the notes on every other page that make the book twice as long), it's that every play must start with a "cast of characters". So before Act I, Arduino, comes "Introduction to the modules" over on the wiki. I also put in some definitions that I thought were useful as a start, so please feel free to add to the list!