There is an artist in Toronto called Posterchild.  He repurposes advertising to actually do some good.  You can read about his work at his blog, Blade Diary.  His most recent work is to make some Toronto information posts actually provide information.  This one tells some information about the tower atop the Canada Life building.

canada life infopost via posterchild

infopost via posterchild's (click through for full post)

It is extremely cool.  I had heard that it was meant to be an airship mooring point but I didn’t know the stuff about weather information.

the story was never clear