Do you have something super special and unique happening for your wedding? Make sure you talk to your photographer about it! Chances are, they could probably help commemorate it for your wedding and/or wedding album.
One of my favorite sessions I've done was for a buddy of mine who was preparing to propose. He's a musician, and he had several guitars that he would wood-burn with meaningful things: quotes, images, etc. When he was getting ready to propose at the open-mic where he and his girlfriend met, he wanted to burn the big question into his guitar. It was super cute, because she didn't see the question until after he sang the song, and came over to get down on his knee.
What was really neat about the whole event though, was that he reached out ahead of time and we did some really cool photography as he went through the process of marking the guitar. They were dramatic images, lots of dramatic lighting, almost a noir-y type of feel. I then got an opportunity to photograph the proposal.
Chances are, if you're reading this, you've missed the opportunity to photograph your own proposal (though maybe your significant other had the foresight to have that done!), but this isn't limited to the proposal process. A friend of mine was getting his bride's ring custom made by a local jeweler, and even though I wasn't his photographer, I recommended he ask the photographer stop in to capture some images. The jeweler agreed, and they have some really awesome images for their wedding album.
You might be doing something that's different from the norm for your engagement, or even something in the ceremony. If it's meaningful to you, make sure you chat with your photographer about getting it captured as soon as possible, so that your wedding album can have that true-to-you flavor!