I forget how I got there, but I recently found two interesting posts about my curious-but-not-very-useful "superpower". This Guardian article (from 2002) talks about animals (and people) that can see into the ultraviolet spectrum. Did you know that raptors can see into the UV? Do you know why that's important? Because rodents -- that is, prey -- emit urine trails, and urine is visible in the UV spectrum (as anybody who's tried to find and clean pets' urine stains knows).
And then there's this fascinating post from someone who sees into the UV (due to aphakia), in which he describes and shows what he sees and talks about some cool testing he did. It's hard to evaluate such things when monitor calibration is in play (do you see what I do on my monitor? probably not), but it looks like "black lights" are lighter and more purple for him than for me.
One of the ways he tested the bounds of his vision was with a simple prism. I never thought of that. Now, where can I find a prism? :-)