plastic bags are generally a big hit with cats. they crinkle to the touch and make fun hidey-holes for games of pounce. some cats take their love of plastic a little further -- they lick it. there are many theories as to why cats prefer the taste of plastic but the most logical explanation is that many bags today are manufactured with potato and corn starches, making them biodegradable. since cats are known to have a sweet tooth for carbohydrates these bags make for a nice mid-day snack.
as always, use caution when allowing your cats to play in bags and remove them if the licking turns into chomping.