Brainfreeze days in science present a different kind of puzzle for the students to solve. The objective is to get students to think "outside of the box" and work cohesively with a group. They participate in Lateral Thinking, Sudoku, Battleship, Tangrams... the list goes on and on.
The students are placed into groups. Each group is then given a puzzle to solve. The groups compete against each other to see who can solve the puzzle first. It's something that is fun for the kids, but also something that challenges their brains in different ways.