Well, there's no built in shake() method or anything of the sort, but it shouldn't be too hard to accomplish! My suggestion would be to store the initial positions of all the actors, generate two random numbers in a small-ish range and then shift the actors by the random numbers given (using one for x and the second for y.) Once you've done this a few times (depending on how long you want the world to shake for) you can just restore the actors to their original positions.