Can you get your boomerang to come back?
Cardstock, a cereal box or (non-corrugated) cardboard
Scissors
Stapler
Cut out two strips of cardboard ~2" x 10"
Align their centers to form an "X"
Staple them together
Bend the four blades slightly up
Hold vertically with bends facing your ear
Throw with lots of spin and a little forward motion
Catch it when it comes back
When you first throw a boomerang, it is vertical and spinning like a bike wheel. As the blades rotate through the air, they create lift proportional to the speed they are traveling. Since the blades are rotating while the boomerang moves forward, the blade on top has a higher air speed than the blade on the bottom. More lift on top would cause the boomerang to lean, but because it's spinning, gyroscopic precession causes it to turn. Forces on spinning objects affect them 90° further along their rotation. This is similar to riding a bike without holding the handlebars and leaning into a turn. The front wheel rotates.
Rather than leaning the boomerang turns and, if it's built and thrown correctly, it will turn far enough to come back to you.