There are some free items on club penguin for the summer party. One is the adventure hunt background which you can get from completing the adventure hunt. The other 2 are:

• Green Safari Hat – Head on over to the plaza and look through the Jungle like trees and vines to find your free hat
• Tropical Bird – Go to the forest, climb up the tree to find this free item. This is like the Parrot that you can wear on your shoulder