This is a very old favorite game, thought to date back to Tudor times at least! It was originally known as Blind Man's Buff. There is also a traditional Chinese version known as "Blind Man" or "Chicken".
How to play: Choose one child to be "it", and blindfold him or her. Turn her round a few times to disorientate her a little, while the other children group themselves around her holding hands. Then let her try to tag one of the other children, once tagged the blind folded child has to correctly identify who has been caught, they then become "it".