I love this idea. An envelope guest book. You just take a store-bought scrapbook/album and glue envelopes into it. Lay out colored pieces of paper for guests to jot notes down on, and then they can place them in the envelopes.
These Striking DIY Terrarium Place Holders are a truly unique wedding craft. Using a clear glass Christmas ornament and a Mason jar lid, you can create little DIY terrariums for each of your guests' seats. Plus, they can act as your favors too.