A type of fabric tape with rubber adhesive that only sticks to itself. Sold in rolls 3/4" wide by 60' long, it is the preferred tape for looming, hodding, or bundling cables together.
http://www.stagespot.com/cgi-bin/shopper.cgi?preadd=action&key=FRICTIONTAPE
http://www.stagespot.com/cgi-bin/shopper.cgi?preadd=action&key=FRICTIONTAPE