Two counselors (or campers) sit on a bench and start talking about how dry, ichy, bug bitten their skin is. One claims that the best choice of treatment is peanut butter and begins to rub the substance all of their arms and legs... the second claims that jelly is better and does the same thing.
The whole time they are explaining why it is a good product and the various ways they use it. This gets more fun when you begin to harrass your partner by saying things like, "Did you wash your face this morning? I hear peanut butter does wonders as a facial." (then smear them) "You know jelly makes my hair glossy... you look like you could use a little yourself!" (jelly in the hair).
The skit ends with a third person walking up with two peices of bread... they exclaim "I love Peanut butter and Jelly!!!" and wipe a peice of bread on each person ... put them together and take a bite.
The kids will talk about it for years. The participants should be sure to wear clothes that they don't mind getting dirty, are easy to get off, and may want to make sure that they can sneak off for a shower right away.