This year (2008) my kids wanted to be Buzz Lightyear and Sheriff Woody. This instructable focuses on the Buzz costume because it required a more unique, creative approach.
I borrowed one of our garden planters and used it as a mold to build up the basic chest structure. The chest piece is made of cardboard, duct tape, masking tape, hot glue, and paint.
I cut, shaped and sculpted as I went.