Redditor Unspeakablefilth lives in northern Ontario, where December was plenty cold (daytime highs of -25C!). He made the best of an icy situation by freezing blocks of coloured ice in shifts, a new batch every 12 hours, ending up with hundreds of them, which he used to piece together a gorgeous ice-fortress that he opened up to his neighbours. The Imgur set does a great job of showing off the build process and the ensuing enjoyment.
It's a great variation on last winter's coloured ice igloo from Edmonton. Can't wait to see what next year brings!