My border collie licks everything. How do I stop it? HELP?

I have a 6 year old border collie that constantly licks EVERYTHING. She likes to lick wet things- the bathtub, snow covered boots, etc. There is a possibility that she could be thirsty, but she has 24/7 access to a water bowl that we have made sure that she is drinking out of. When the family is relaxing in the living room, she will nonchalantly lick the carpet! The whole family feels terrible because we are all constantly yelling at her, maybe 20 times a day... But she doesnt understand. Normally she is a very attentive and tuned in dog, and she is not overspoiled, so we know she just would not ignore us. She just mopes away sadly and licks something else! She licks peoples legs, licks the floor in the kitchen even when nobody is cooking, licks walls, doorhandles, EVERYTHING! We cant put hot sauce on stuff like some people might say, because some things that she licks we cannot put hot sauce on (the cat). What do we do to break her of this habit?? Also, I know border collies need a lot of stimulation, and we normally take her outside to play fetch and do agility for several hours everyday, but right now she has a hurt hip. If the bad habit is from sheer boredom, what are some non-strenuous activities I can do with her indoors to entertain her? Nothing that involves treats- her bedrest has gotten her a bit overweight.