If you're in a carpeted room, get some generic hook and loop tape and a bottle of Aleene's Tack It Over and Over glue.
Glue the back of the hook part of the tape and let it dry overnight or 24 hours. Cut into 3-4" sections and stick them to a heavy plastic bag. Put two or three sections on the bottoms of your pedals, sticky side down, and they'll grab your carpet just enough to keep them from wandering. :)