Instructions
Access the avatar editor from the main menu of the Xbox 360 by selecting the "customize avatar" button. This option is found by pressing A while hovering over the avatar's profile on the menu.
Choose the marketplace option to see the list of available clothes and props for purchase.
Scroll through the lifestyle collections sets and enter The Muppets sub menu. This area holds two sets of Avatar gear from both "The Muppet Show" and "The Electric Mayhem" series of Muppet items.
Browse the costumes, clothes and props from the two Muppet series to see how they look and interact with your avatar. Some examples found here include the "Animal Costume," "Boomerang Fish" and "Remote Control Pie."
Select the items you want to download, and press A. This brings up the Xbox 360 guide feature asking you to confirm your purchase. If you have enough Microsoft points in your account, select "confirm download" to add the item to the avatar editor.
Return to the avatar editor and apply the Muppet-themed item that you downloaded. The avatar gear is automatically filed in its appropriate section, such as the "Swedish Chef costume" in the costumes section of the avatar editor.
Use the option that reads "save and exit" to confirm the changes to your avatar before exiting the avatar editor.