Martin,

Have some "speed" events set up to practice basic skills. Something like an indoor Seneca run:

-Knot-tying station.
-Setting up/tearing down a freestanding tent or shelter. You can use dumb bells (iron, not people) as dead man anchoring points for a primitive shelter.
-Repair some torn clothing from the backpack sewing kit
-Have them tie some of the knots blindfolded.
-Set up first-aid scenarios: make a litter, sling an arm, etc

-See who can burp the entire alphabet in one burp.

-A knife sharpening "clinic"
-Discuss home and camp fire safety