This effect will make a nice explosion. Perfect for those "clashing" banners.
1. Start a new image. I used 640x480 and then cropped the final result.
2. Color the image in black.
3. Make a new layer. Change the foreground color to white.
4. On the new layer, select a custom shape with a lot of edges. Be sure that the shape is set to Fill Pixels, and make make a cluster of shapes in one area.
5. Edit > Stroke ( Width - 1 Pixel, Color - Color you want, Location - Outside, Blending Mode - Normal, Opacitiy - 100% ). Do that twice.
6. Filter > Blur > Radial Blur ( Amount - 100, Blur Method - Zoom, Quality - Best ).
And there you have it.
Creator