Hey, Doug, this one's for you, LOL! This colour is absolutely genuine, no kidding! I have no idea what species it is, of course, but isn't the colour amazing? Seen this afternoon in the woods at Bowness Park. Added August 2009: thanks to Flickr member oloesel for the ID, Cortinarius iodes. Much appreciated!
Information, received with thanks, from Dr. Suzanne Visser at the University of Calgary:
"I haven't seen any mushrooms in the Calgary area with an intense purple cap such as this one has. I'm not sure about it's identification, but it may be something in the "Gomphidius" group. I've seen "Gomphidius glutinosus" many times in the same area that you saw this one, and, although this species can have a violet cap, I've never seen a specimen with a deep purple cap. Nevertheless, I think it may be either a variant of this species, or perhaps another species in the same or related genus. The slimy cap, dark spores (you can see them on the stem where they form a dark ring) and white tufts on the stem suggest it is either "Gomphidius glutinosus" or something closely related to it. Also, it looks like the base of the stem is yellow (do you remember if it was?), and, if this is the case, it probably is "Gomphidius glutinosus", since this species has a bright yellow stem base. The purple color is spectacular though; maybe, the color intensifies as the temperature falls."