Drop this script on your object, run the game and press spacebar to see the outline appear/disappear:

private var shaderNoOutline = Shader.Find( "Toon/Basic" );
private var shaderOutline = Shader.Find( "Toon/Basic Outline" );

function Update() {
    if( Input.GetButtonDown("Jump") ) {
    	if( renderer.material.shader == shaderNoOutline )
    		renderer.material.shader = shaderOutline;
    	else
    		renderer.material.shader = shaderNoOutline;
    }
}