As a change from running a Treasure Hunt - here is a great childrens game. Follow the links for other party games to entertain your kids:

Pairs

Prepare by gathering together items that are commonly thought of together. E.g. a knife and fork, a cup and saucer, a matchbox and its cover, a shoe and sock etc. Wrap each item in paper. You need to have one item for each player.

Give each player a wrapped item. At your signal, the players must unwrap their items and seek their pair. As each pair finds themselves, they may be given a small reward.