Well I found myself running around riften fairly bored when I jumped onto the blacksmith forge (therefor catching fire and burning myself) and lo and behold my destruction skill increased.

Bug? Intentional? (Probably not) Has anyone else experienced this?

Edit: For good measure I jumped on it a tad more to see if it actually increased Destruction, and it totally does.

Well, I could see this being intended (or incidental) if raising Destruction skill also raises resistance to Destruction-based spells.

I'd heard about this before and even tried it. IIRC, I tried it in Whiterun and nothing happened. Maybe it's peculiar to Riften due to it being powered by Fire Salts? But that's a Conjuration thing.

Maybe I didn't stand in it long enough. How long did you stand in the forge?

I found simply standing in it will only hit you once, and by jumping it will hit you every other jump.

I wasn't even able to jump into the whiterun forge ;p, so I assume all open-top forges may do this?

This is documented on the UESP wiki, and relatively well known. But it is one of the most tedious ways of gaining experience in anything.

Which ever it is enjoy an easy boost in stats, why not use the base healing spell while standing there to raise Restoration as well