This is what I did last time:
Two years ago at the first fest I included info for our group (photos of our dogs and cats available for adoption, newsletters, and applications for spay/neuter assistance). Since the fest was in October I also had handouts for the children to take home (‘find the items that can make your dog sick/scared on Halloween’, ‘help your lost kitten find its way home through the maze on Halloween’, etc.) I also had a game where the children rolled a wooden dice and depending upon which color it landed on they were able to take a small item from bushel baskets – all items were dog/cat related (like book markers, rescue bracelets, etc.) I had almost no time to prepare and little knowledge of the concept of the fest.
Although it was easy to put together and run and the children seemed to like it, I didn't want to hand out a bunch of junk (I purchased many of the prizes from Oriental Trading) and papers. It seems a little contradictory to the whole idea.