If you just want the outlandish effect you can use TopazAdjust plug in (for PS and a few others).
You can get effects like this:
That's not a particularly drastic example, but have a browse of the topaz adjust group on Flickr, to see the types of things you could do. You can also use the plug in to get quite natural effects, that are not dis-similar to 'real' HDR (i.e. adaptive exposure to bring out a higher dynamic range, rather than just to cartoonise the pic).
As you can see in the above pic, you can get quite a bit of fringing (? is that really a real word?) using this.