When you're not the primary photographer at an event, you have more freedom to experiment. I just read an article with good suggestions for adding creativity to your shoot, 7 Ways To Be More Creative At Your Next Wedding. I'll add one of my favorite tips too.
I like to get the bride and groom in a different setting nearby to change the look of the album. Sometimes I feel like the shots are all starting to look the same, so by finding a new context, I can jazz things up a bit. Once you have the couple isolated from the guests for a few minutes, encourage them to play. They're more likely to "let their hair down" if they don't have an audience staring at them.
Photo by Derrick Story, captured with a Canon 5D, ISO 400.