I'm doing something at my wedding that my mom saw at a friend of our's wedding. While the bride and groom are getting pics done during the cocktail hour (which is unavoidably time-consuming), you can entertain them while they wait AND create memories from your wedding! You can vary the details, but this is the idea:

Buy a binder or some type of photo album. Dedicate each page (or half a page) to each guest/family at your wedding. We're putting ours at a table in the front of the room as they walk into the reception. Have someone take a picture of your guests as they enter. You can use one of those portable printers to print the pictures right there, or leave room in the album to paste the picture later. In their designated "space," each guest/family can write a message to you and your new hubby! My friend also had little stickers and other crafty decorations so they can spend time decorating and not being bored waiting on you guys.

We're also having a chocolate fountain to entertain them and serve as a conversation piece.