Guestbook Ideas

I am brainstroming for alternative guest book ideas besides the regular sign-in book or picture album.

Here are my choices:
1. Wishing Tree
I have 2 of these 5' Silver metal tree.....so i figure wishing tree is great!
http://www.shopwildthings.com/mecatrswclbe.html

2. Guest book calendar

3. Photo puzzle guest book

1. from http://classifieds.weddingbee.com/topic/wishing-tree-038-card-box-038-easle
2. from http://www.invitationsbydawn.com/
3. from .http://greenweddingshoes.com/real-wedding-sarah-justins-sweet-smog-shoppe-wedding/
They all look so fun :) Which one is your favorite?