I made these the other day, seriously they were really simple to put together and I was able to get them done in a nap time. I used the pattern Simplicity 5105 and to fill it I used pillow filling. The big bags of it were on sale at JoAnn's (I might go get another bag and split it between the two) plus then it will be really easy to wash if needed.
Here is the one I made for my daughter.
Here is my son's.