A new Costume Trunk catalog is out at the Stage for the new Penguins That Time Forgot (January 2013) play!
To find the Grass Skirt:
Step 1. Go to page 4.
Step 2. Click on the purple penguin's arms.
To find the background:
Step 1. Go to page 6.
Step 2. Click on the green penguin's hand.
There are no hidden item cheats, but there is still some pretty cool costumes to check out.
For more Club Penguin catalog cheats, click here.