"Have someone in charge of taking Polaroid pictures of the guests as they walk in. After the picture is taken, have them insert them into self adhesive photo corners in the sign in book and write a note next to it."
Wedding idea: get a polaroid camera, put on a table with a notebook, some glue sticks and pens and get guests to take photos of each other. Stick them in book and leave a little love note for the happy couple!
At Meagan and Wes' wedding they set out a polaroid camera, guests could take a picture of themselves (or get someone else too if they didn't want the MySpace like selfie) and then glued it into a book and wrote their message beside it. This is great as years later you will be able to put a face to the name.