teeterboard

A board with one end raised so that when an acrobat or tumbler jumps onto it, another performer standing on the opposite end is tossed into the air.

A seesaw; teetertotter.

A similar board used by acrobats that sends a human into the air when another human jumps onto the opposite end.

a plaything consisting of a board balanced on a fulcrum; the board is ridden up and down by children at either end