"Hi, are you familiar with KDE?"
...figure out what their knowledge level is (kde/linux/etc newbie/user/dev), personal or business, if they've seen 4 yet...
(Add responses here!)
booth items old list
Talking points that can be used for brochures, etc. Could be translated.
happy newbies this probably duplicates other work
http://www.kde.org/getinvolved/promotion/ has some information