I love dressing up for MNSSHP!
In 2007, I bought a hula skirt, and a pink tank top and wore a Stitch backpack and I was Lilo & Stitch.
In 2008, my boyfriend at the time and I made The Incredibles baseball shirts, where his said Mr. Incredible, mine said Mrs. Incredible, and on the back was The Incredibles with our ages.
In 2009 I went twice. Once as a Mouseketeer. Then I went with my mother and sister. I was a Stitch football player, my mother was a ghostbuster and my sister was a fire woman. My mom & sister bought their "costumes" at wal-mart, they were just t-shirts with a few accessories. Very simple!
I see many adults dressing up, but my favorites are the huge familes who do group things. There are a lot of Peter Pan groups & Toy Story groups. It is, in my opinion, the best time of the year in Disney.