I have seen it used on counter tops. If you have a storage/toolshed, summer kitchen, fish cleaning station of anyplace that might need a water proof counter, it could be used there.
Drawer/cabinet liners could be another choice.
Use it as underlayment for a new roof on a chicken coop or other small out building instead of tar paper.
Use it where regular flooring needs a little extra protection, such as under the refridgerator or stove or water heater.
You could cut small pieces to fit inside your shoe and boots to be used as "comfort soles" or to help waterproof them further.
I use pieces to make flooring for dollhouses.
Cut pieces for "dinner mats" like the vinyl ones that people buy at Walmart. We put them under the kids plates so their mess will be easier to clean up after they eat.
Keep a piece in the trunk of your car for stuff that may spill or get the back dirty when you are transporting it.
Coasters for your beverages so not to leave stains on furniture.
Pieces of it rolled up and stapled together would make excellent substitutes for "sona tubes". A sona tube is a clyinderial tube used to pour concrete into a pier shape for foundation construction.
Ernest