Hi Danielle,
Mickey's Very Merry Christmas Party is my favorite special event at Disney World! In fact, I've attended it the last 2 years in a row and I just bought my tickets today for this years Party.
Simply put, it is spectacular! You'll be mesmerized by the Castle Dream Lights, Holiday Wishes fireworks, enjoy cookies & hot cocoa, be captivated by Mickey's Once Upon A Christmastime Parade and so much more. My favorite part of the Christmas Party is the experience of walking down Main Street towards the castle, while "snow" is falling around you...it's indescribable.
The majority of the attractions will be open, but you may decide to just enjoy the special offerings that night instead.
If you click on the link that I provided above, it will give you a place to input your name. After you do that, click, "OK" and it will play a video featuring some of the exciting things in store for you.
Have a magical vacation,
Kaylene