Battle of the Books:
for us...5th graders through the public library. Teams are 3-5 kids who read from a list of 15 books. (And no, my girls are not reading all of them. they are going to be sad once that battle happens!)
then in 2 weeks we battle...all the teams across town from all the elementary schools. 50 questions and every answer is the title and author from the book list. The groups have costumes and it's a big, big deal!