I'd definitely recommend SF Math Circle to kids who are curious (and not necessarily interested in math), enjoy working with others, and are into experiential learning. My kids have participated at the SFMC elementary school, middle school, and summer school programs. They really enjoy the "gaming" approach to teaching mathematical concepts used in the SFMC curriculum, and have discovered ways to think logically and creatively by studying codes, paper folding patterns, playing card puzzles, and other activities shown by the instructors.