If you are looking for a way to hide a key outside, a pill bottle makes a great weather-proof container. With a rock to disguise the top, you can tuck it into a rock garden or partially bury it to hide its location.
Mosquito trap - No more mosquitos!! Cut the top off a 2 liter bottle. Invert the cone and place it inside the bottle. Glue the two pieces together. Add 1 tsp yeast and 1/2 cup sugar to some luke warm water, and pour the mixture into the bottle. Mosquitoes are attracted to the carbon dioxide that you exhale. The yeast feeds off the sugar and emits the same gas, so the mosquito enters the bottle, thinking she will find food there. FLIES LOVE THIS!!! Have caught 1000's of flies!!