This tutorial will help you make a nice 'action' background.
1. Start a new image. I used 640x480.
2. Set the foreground color to black, background to white (or simply hit the 'd' key).
3. Filter > Render > Clouds
4. Filter > Distort > Ripple (Amount - 900%, Size - Large).
5. Filter > Blur > Motion Blur (Anglie - -55, Amount - 50).
6. Filter > Brush Strokes > Accented Edges (Edge Width - 4, Edge Brightness - 33, Smoothness - 8 ).
7. Image > Adjustments > Hue/Saturation and add some color to the image by selecting the 'colorize' checkbox.
8. Duplicate the layer.
9. On the new layer, do Edit > Transform > Flip Horizontal.
10*. Set the layer's blending mode to Soft Light.
The end, cropped result:

* - This step can be also be done with Overlay, Darken, and Multiply for some other cool effects.
Creator B)