Create an awesome light show using nothing but Ender Dragons! You will need 2 command blocks however; a chain command block and a repeating one. Extremely simple and no lag either!
Remember to connect the blocks properly! Place them next to each other, with the top arrow of the repeating to the top arrow of the chain, leading away from the repeating one, like so:
Don't mind the /trigger written. I did not have my screenshot so I borrowed the image from the web.