Download this config file and put it in your Phun installation folder.

exit = {System.exit};
App.simRunning = false;

time = {System.time};
sin = {math.sin};
cos = {math.cos};

groovyOn = {
	App.fadeColor = [0.8, 0, 0.9];
	App.fadeTranslate = { [3 * sin(time), 2 * sin(time)] };
	App.fadeRotate = { sin(System.time*1.2) };
	App.Background.skyColor = [0,0,0,0];
};

groovyOff = {
	App.fadeColor = [0, 0, 0];
	App.Background.skyColor = [0.3, 0.4, 1, 1];
};

Keys.bind("f4",  {Sim.gravitySwitch =  ! Sim.gravitySwitch});
Keys.bind("f6", {App.drawBodyCenters =  ! App.drawBodyCenters});
Keys.bind("f7", {App.drawVertices =  ! App.drawVertices});
Keys.bind("f8", {App.drawCollisions =  ! App.drawCollisions});
Keys.bind("f12", {System.screenshot});