Here's a nice simple pattern I call the fish pattern. In this pattern, two edge pieces next to each other are swapped over to the opposite side. If you hold the cobe diagonally, the pieces (the Pisces?) that remain look like a fish - the fins, nose and tail being the four corner pieces. In the picture here, the green fish is on the top layer, swimming away. There's a purple fish on the bottom layer too.
Making this pattern is simple. It's just two 180-degree twists, repeated three times. Have a look at the video below, and you're sure to get it.