Man, that snow fort w/ Slide is awesome! The web page is cool too. Blocks are made of 5gallon jugs--- can't imagine how much snow that is for that fort... simply amazing. Props.
When I was a little kid living up north, one year a buddy of mine's parents watered down the snow near his jungle gym one night. The next morning there was a 10x8 block of Ice around it that was smooth as glass. We ice skated on it for a while, but, it was too small really.
So, that day when I went home I wanted to build my OWN ice skating rink. Got permission from the rents and set up the sprinkler and hose in the back yard over a larger area of fallen snow. Well, it turned to ice, the whole freaken back yard was a 3-4" deep sheet of it. Unfortunately it froze very uneven so couldn't be used for skating. However, it was very slippery and with a little momentum a sled would shoot right across.
We had a lot of fun that winter. In the spring when the snow and ice melted, the once grassy back yard was nothing but mud. Soggy, brown, mud. The grass eventually came back but not as quickly as years past without my ice treatment. Never did that again, but, a lawn sprinkler and some clean snow fall can make for some interesting projects. 😛 (Remember to take the hose and stuff back inside after shutting it off, or it'll freeze too and probably break thehose,etc.)