I had two to three interviews before they offered me a contract. During the interviews they try to hide as much information as they can. If you don't ask few times you won't get the much needed information regarding the working hours and the whole system of work in the company. During the interview they ask you if you're willing to make fool of yourself in front of 800 - 1000 people. Are you shy... Can you manage the kids and keep them calm?

Casual interview, make sure to read up on the company and be knowledgeable of all the programs such as summer camps and after school programs. Past experience working with children is a plus. Brush up on some basic chemistry.