We just did a bowling party for dd's 5th birthday. It was really difficult to find themed favors, so I did what another poster also suggested, I bought a plastic bowling set and cut a slit into the top and filled with candy, pencils, etc. I found colored plastic tape in primary colors to tape up the slit and tied curly ribbon and a laminated thank you to the top. Also, I lucked out and found black water bottles shaped like witch cauldrons at the grocery store after Halloween, they were marked down to a quarter each. They looked enough like bowling balls to me and I used a silver sharpie to write each child's name on them. The party package came with a bowling pin for the children to sign, that was really nice and if you can find one, I think it's a great souvenir for the birthday girl.