Each summer is split into 9 weeks. Within those 9 weeks, you typically have three 3-week programs/courses. One of those 3-week periods would be open to "leave" or vacation back home. The order of which these activities fall is generally randomly selected, but there is some input based on planned family activities. Students can opt for summer school during that leave period to either retake a class they failed or to get ahead and reduce the load on the future semester. As an example, I took thermodynamics and astronautical engineering over the summer to avoid them during the school year. You have 1 class, but attend it all day/every day for three weeks.
The rotation has changed over time, but long ago, this was the rotation schedule - others can chime in with the current experience.
Summer after 4 degree year (in no particular order)
Block 1: Leave
Block 2: Aviation program (soaring, jump, drones)
Block 3: Combat Survival Training (no longer offered to my knowledge)
Summer after 3 degree year (in no particular order)
Block 1: Leave
Block 2: Leadership (running another program on camp like BCT, Sports Camp, Summer Sci, etc)
Block 3: Operations Air Force (go see a base and look at life in the Active Air Force)
Summer after 2 degree year (in no particular order)
Block 1: Leave
Block 2: Leadership
Block 3: Leadership