Making a fake HDR in the GIMP

I just was over at digg and I saw these steps for making a fake HDR (Thanks, Elliuotatar).
By doing this, you can make an HDR from a single JPEG, instead of needing a bunch of files (the quality is not as good, though).
1. Duplicate image to a second layer.
2. Image->Adjustments->Desaturate second layer. (Make it black and white.)
3. Image->Adjustments->Invert second layer. (Make it a negative.)
4. Do a 64 pixel gaussian blur on the second layer. (Low pass filter. Prevents loss of high frequncy contrast on surfaces.) Edit: You can just use regular gaussian blur at about 5 to 15 pixels.
5. Set the second layer to soft light.

This works in Photoshop or The GIMP.
And there you have it. If you want to see some real HDR images, Stuck in Customs from flickr has over one thousand of them.