180° rotation rotates the piece 180 degrees. In some games, that can be actually done. It grossly depends on games.

In tetr.js, it does two clockwise SRS rotations. Therefore no new spins can be done.

In DTET, pressing rotate left and rotate right at the same time will rotate 180° with counter-clockwise wallkicks.

In Tetris, space button rotates 180° with counter-clockwise wallkicks.

In Tetris Best and Tetris Best 2, there are separate buttons that rotate 180° for counter-clockwise and clockwise wallkicks.