Have you heard of magnetic nail polish? You probably have but I was a little afraid to buy it. My friend let me try her's and it is pretty neat. She found her's at Target (where else?).
Get your nails already to be painted. Then paint on the first coat and allow to dry. On the second coat, make sure to put it on thick. You also want to work fast! After you paint one nail, put the magnet (that is on the bottle's lid) over the nail. You will want to move it side to side carefully so you also get the sides of your bigger nails. Learned this the hard way. The magnet has a reaction with the nail polish and creates a ripple look. Pretty cool!