Ooh I'd give them all an egg, a dragon egg, - bejewelled and decorated - and take it down creative direction. Each group has to keep their egg intact for the whole lesson. And they have to describe the dragon inside. what are its powers? What does it look like? Where does it live? Get an adult to scribe for each group and get each group to orally feed back to the class.
Probably not at all what they;re looking for but that's my first thought!
Thanks Definitely no bums on seat -not my thing at all ,just feel very constrained by the time limit .Give me an hour ,an outside space,and lots of opportunities for writing and problem solving and I'm a happy teacher... Food for though though,thanks