If you've ever considered a polaroid guest book, do it! It was so fun and mrp and I cherish our book and all the adorable and the absurd pictures our guests (and even I) took. I originally went with it because it fit in with our photo theme (framed photo decorations, the cake, the table numbers, etc.) But knowing what I know now, I'd get it no matter what just for the fun value!
Here's my sister kicking things off.
I'm taking a very cute shot of my bridesmaid and my cocktail :)