also: Hook and Loop fastener
Velcro is the brand name for fabric Hook and Loop fasteners. is highly conductive and good for making switches or connections that might need to be opened and closed.
It has been used in various projects:
Conductive Velcro Toggle Switch by AnaLou >> http://www.instructables.com/id/Conductive_Velcro_Toggle_Switch/
Conductive Hook and Loop switch on Syuzi Pakhchyan’s headband, see her Fashioning Technology book >> http://www.fashioningtechnology.com/
Adrian Freed at CNMAT came up with a cheap alternative to make your own conductive Velcro by simply putting some in the hook side of the Velcro and then stitching some into the loop side.