As an aid worker in childcare, you will be working with less then perfect conditions and children, who will probably be apprehensive. You can also expect a lack of resources. Reading is a good way to keep the children entertained and you will probably have access to books. However, if you don't, tell the children your favorite story or make one up. If you have children in the group who are old enough, let them read or tell stories to the others.
Creating things is a good distraction for children. See what kind of things are available and that you can use with the children, like paper, glue, scissors, coloring pencils and paint. If there is nothing useful available, try to be creative with things you can find. For example, you can pick a small tree and then look for things like strings, paper or whatever else you can find to decorate it.
Singing makes people feel good. Ask the children about the music they like and sing one of their favorites. Alternatively, you can teach the children how to sing a song they didn't know before. You can also hold a talent show in which children perform songs of their choice and then decide among themselves who was the best, who came in second and who took third place.
Divide the children into groups. The point of charades is for one group to come up with a word and tell the word to a single member of the other group. The chosen member has to make his teammates figure what the word is but is not allowed to speak at all; all he can do is use his body to act out the word. You can decide to pick words from a particular theme like "movie stars," or "food and beverages," but you don't have to put any limitations on the game.