Out of powdered sugar? You can make it yourself!
I picked up this little tidbit from my "More with Less" Cookbook, and have found it to come in handy in a pinch!
1 cup granulated sugar
1 Tbsp cornstarch
mix together in a food processor until fine and powdery
It took a while for mine to come out, but it worked just fine for the icing I needed it for, and saved me a mad dash to the store and back.
I've been thinking it would be nice to find something without the cornstarch or the bleached sugar. So, inspired by that recipe, I searched the internet some more ideas and found this further gem for making unprocessed powdered sugar out of sucanat from Heavenly Homemakers.
Such a great tip, if you don't require a pure white icing/frosting/powdering!