Camp Catapult Ages 9â18 â¢ Mon-Fri, Half Day (9:00 amâ12:00 pm) â¢ $195/week Siege Alert! Look out, itâs time for flying tennis balls, eggs and bags of Jell-O as this camp offers participants the opportunity to design and build a table top size catapult or trebuchet. Students start with a kit of wood, steel, aluminum and plastic parts and create their catapult. When students finish their inventions, they field test them in a fun and exciting activity. Students can keep their catapults.