There were a few activities organised for the kids while we were at Rotorua. The first was a Pirates of the Caribbean challenge, where each boat team had to earn pirate gold (well, it was silver, actually, and does it count as pirate money if you earn it?) by completing 6 or so challenges, while avoiding the Black Pearl (below) which was patrolling the area. If you were hit by a cannonball from the Black Pearl you had to do whatever they said (e.g. starjumps, racing, giving up your gold) and if you refused they would stab your boat and you'd have to go and get it repaired before you could continue with the challenges. It took half the afternoon and everyone had a great time and got totally worn out.
On another afternoon there was a slip-and-slide on a big sheet of black plastic. Unfortunately it started raining but the boys still had a great time. There were a whole lot of other kids on it but I'm a bit reluctant to put other people's kids on the internet