On a more up to date area, in order that the government here can get it's take on business in restaraunts, which is mostly cash, they have introduced an official receipt which has a scratch card on it.

The stubs from the books of official recipts are then used to assess the tax due. It has been very successfull as all Chinese like the idea of winning money.

If you uncover the scratch area and it says the equivalent of 'thankyou' (xie xie) then you have won nothing. But there are cash prizes. To date I have won the princley sum of 20 yuan (about US$2.5)

Still it keeps me hoping....