Each camp department runs its own Special Interest Program (SIP) at 4:00, the hour after the fourth merit badge session. These sessions vary from department to department and range from teaching useful skills to simply offering fun activities in the scout's "special interest" be that first aid, rifle shooting, handicraft, etc. Some SIPs might teach skills required for a merit badge or rank but generally it will not cover an entire merit badge like an earlier session would.
Scouts can spend all five days of the week at the same SIP, mix and match with different SIPs, or not go to any SIP if they so choose. Scouts that attend four of the five days at the same department, however, will receive a special segment for their uniform.
The SIP hour is often used by scouts for different things other than the actual programs. Many like to take an extended siesta and simply rest in camp. The pool offers a "free swim" during this time for anyone wishing to cool off. Scouts trying to earn difficult merit badges might use this time to do their "homework" for those classes. The Troop often uses SIP as a time for extra marching practice. Other scouts will take "Shower SIP", heading off to the scout showers at this time every day.