The same baby shower that I made the quilt for, I also did invites. After completing them, I realized I could have created a much simpler version, but such is the downside of being creative. We aren't always practical. I made garland for it too (pictured below) which unfortunately we didn't end up using, but fortunately for me I kept it and hung it up in my bedroom - an easy way to brighten up an apartment bedroom.
It was a book themed baby shower, so I used a book-fold format for the invite (so obvious, I know) hoping it would have the feel of an actual book. I also included a removal book plate (printed on sheets of sticky label paper). I got the idea for the book plate addition from here. Everyone bought a book for the new baby girl, and this seemed like a good way for everyone to personalize them.
If you are thinking about hosting a book themed baby shower, you must check out this one created by the people at Martha Stewart. Amazing! And it even comes with free downloads!