On the practical side, this laser is an excellent long-range level for landscaping and would make one heck of a beacon for lost skiers/hikers (just follow the line and here I am!)

On the fun side, I would plan on using this at the museum of natural history. There is a huge display of various colored crystals just waiting for the Lite-Brite treatment! Option two is to tie the laser to a small rotary device (model helicopter will do), place it up high outdoors in the rain (shielded) and see what it looks like to stand underneath and look up.