A Bicycle Rally  We did this for my son's 9th birthday.  We planned our route very carefully, we felt that the kids could cover 12 km in 2 and 1/2 hours. We set up four check points along the route. Our ratio of adult cyclist to children was 1 to 4 for supervision, and we had a vehicle follow behind incase of spills, crashes or bike's breaking down.    Each child was asked to bring a knap sack to gather their loot on the ride. At the first check point we had them searching for a bag of jacks each. This was a good exercise and we did not move on until everyone had found a prize. The second check point was a refreshment break about mid point in the route. We had water bottles and power drinks that they could sip and take with them if they wanted too. This gave everyone a chance to catch up.  At the third check point we had set up tin cans that they had to knock over with a sling shot and a stone.  This was a very time consuming check point, but provided a great deal of fun. When the children headed back to our place there was one last check point.  We had a craft that they made with a tennis ball and some string.  They each had to poke the string through a slit in the tennis ball and make a toy.        By the time they reached out home, we had make your own tacos ready for them. This was a bit messy. Other suggestions would be Submarine sandwich platter or the old stand by, Pizza. All in all it was a great adventure.  The kids were tired and happy by the time their parents came to retrieve them.