What to do with thousands on unused red telephone boxes? One idea is to remove the coin-operated telephones and printed phone directories and put library books inside instead. A kind of mini-mobile library if you like. The idea obviously depends on trust (you take one and put one back) and is open to vandalism, but the cost of trying is so low why not give it a go?
How about putting wi-fi nodes in them and making them into (a) access points for nearby people who need high bandwidth and (b) quiet places you can step into while talking on your mobile?
I like both, but especially the silence booth!