Is your four and five year old in school?
My 4 year old will be going to a Montessori summer program. They go year round, but she is starting with the summer program and then will transition into the regular program in August.
Their summer curriculum is geared in a more relaxed direction. They have more filed trips and different activities than during the regular year.
The summer program is from June 2nd through August 8th and then the regular program will begin.