Today we built an igloo in my front yard.
It was first a pile of snow, but when we dug it out it looked like a real igloo. The cool part of an igloo is that when you dig into the pile, you take out the snow and build walls beside the entrance.
Here is a link to an old movie about building an igloo. Its pretty cool how they build the igloo. They can do it in about 2 hours.