Sara - If the children's museum is a member of the Association of Children's Museums, you should get a copy of their "case statement for children's museums," which they came out with several months ago. We used it and found it to be very helpful in developing our own case statement for our children's museum's capital campaign. There are studies cited that can be helpful in grant proposals. General operating grants are tough for children's museums - we have had our best luck with local banks and foundations. Feel free to contact me if you want to discuss any of this further.