So if you don't know who Piggie and Gerald are then you must not have an elementary age kid in your house (and if you do and don't know who they are you need to go to the library!!) The Piggie and Elephant Books by Mo Willems are my son's absolute favorite. He has read every book about 30 times each. I hear him in his room at night giggling and I know he is reading about Gerald and Piggie's shenanigans.
So when I am faced with a theme for my 7 year olds' birthday party my first thought was Piggie and Gerald. So I will continue to add to this post as I create more and more for his party in 2 weeks, right now I finished a couple applique tee shirts with his favorite characters. I just did a simple applique- using felt so it won't fray and I didn't have to zig-zag stich making the outline intrusive to the desgin.
I also designed a comic book style invitation for the party.