I have some seriously cute invites I designed, if you're interested, and addressed them by hand, ie. Duchess Stephanie of High Point (the name of their street or town if the street name was corny; you can also add "dom" to the name of a simple street to fancy it up, ie Henry Lane becomes Henrydom or dome, or shire, ie. Henryshire). I reserved the title of Princess for the birthday girl when I did it, the attendees were Dukes and Duchesses. I also had my son dress as a night, made up a fancy pillow, then we rolled the invites which were tea-dyed into scrolls with ribbon, and hand-delivered them with him getting on his knee ala Cinderella. It was a scream! Everyone LOVED it and everyone came to the party. At a kindergarten party, kids received a "ticket" to the Millenium Ball (it was 2000) that they then gave a parent to be admitted (we had extras on hand that we gave in line if they forgot theirs). You could do that, then pair boy/girl or girl/girl, etc. and announce them as they enter, ie. The Lord Jacob of Derbyshire and Duchess Alexandra of Williamston.
At school parties, I've had the kids do "The Stroll" by the Diamonds which they enjoyed. That would be something fun and simple you could show them, or perhaps a little minuet, or, a Monster Mash dance?