HI PresidentJen!
Good to hear from you. One suggestion is for you to post this question in our PTO and PTA leaders group. It's a really active group and you will likely get more responses.
This year we are adding a free throw contest to our Halloween Social so there is something the older kids (grades 3-5) will enjoy. We are planning to charge a small amount for registration, and they can purchase an extra try as well. There will be big prizes for top finishers in each grade.
I am not sure what kind of turnout we will get, but my main concern is fitting the competition into our timeframe (1 1/2 hours). If anyone has done a free throw contest, can you tell me how it worked?