Step 1: Create a blank 400px by 400px document and fill the background layer with a solid black colour. Now select Filter > Render Lens Flare from the menu, and create a simple lens flare in the middle of the image.  Leave all the settings on their defaults.

Step 2: Now, using the smudge tool, start smudging the lens flare from the centre to the outer tips. Follow my example to the left, making sure you have the following tool settings:

Brush Size - 27px
Mode - Normal
Strength - 50%

Step 3:  Now to randomize our image a little further. Go back to the main menu and choose Filter > Distort > Wave. Play around with the settings until you have a result a little like mine on the left.   Of course, you can also just click the 'randomize' button until it settles on something cool. Either technique works just fine.

Step 4:  Layer > Duplicate this layer and repeat step 3 with the new layer.  Finally, set the top layer's blending mode to Screen, and move it about until it looks cool.   Repeat this as often as it is required to suit your own personal tastes.

Step 5:  Now simply merge all the layers together with the Layers > Flatten Image menu option, and there you have it - a cool little abstract of your very own!  As an optional step you can even use the Image > Adjustments > Invert command to create the negative image shown off to the left, and/or give it a little colour with Image > Adjustments > Hue / Saturation.  Its all up to you really.  Have fun!