HDR from multiple exposures is just assembling a file with a floating point value for each pixel, rather than an integer. The tone mapping then uses said floating point to assign a value between 0-255 by reducing the dynamic range. The trick is that last step whether you get good or garbage. Otherwise, a HDR file just contains more information than a normal pic.
While this isnt a particularly artistic image, its still a tonemapped image from a HDR file based on software back in 2005 (which is admittedly before the HDR craze and more back in the papers being shown at SIGGRAPH)
http://dl.dropbox.com/u/14210505/HDRGarden_1.jpg