Run, don’t walk, to play with the Mandelbrot Maps applet, which lets you play around with the Mandelbrot set while seeing the associated Julia sets updated in real time. This fantastic applet was created by Iain Parris, an MSc student of Philip Wadler at the University of Edinburgh. There’s even a short screencast of Iain explaining the math behind the Mandelbrot and Julia fractals and showing some of the cool things you can do with the applet.