AdAge reports that an American company is using currency for its adverts. Boodle, an online coupon company, is affixing circular inserts featuring its trade mark and a slogan on the back of 25 cent pieces which it will leave in the returned change slots of vending machines, payphones and the like. The inserts are removable to avoid damaging US currency, which is an offence in the States.
The IPKat says, are there no limits to where those intrepid little trade marks will get to?
More things to do with money here and here