h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Another game that can be played at the check-out is 'Guess how much this is going to cost'. This is a two player game, preferably played with your partner. The person who guesses the closest figure to the total of your purchases is the winner. The loser pays for the shopping. You can add penalties, such as, if the loser is more than £10 out they have to ask for 'cash-back' too.

Another game I've found very satisfying is to pretend not to speak the checkout operator's language. I'm British and live in Japan so this is easy and convincing. Just say "pardon" (or whatever you like in any language) and get the operator to try to communicate with you. This can be done with every question he/she asks. See how long it takes before the people behind begin to tut tut or the operator is thrown into a panic and decides to call for help (this also can lead to a lot of tutting). In Japan this is a great game because Japanese are very polite, very reserved and don't like to complain. Moreover, they are also very sympathetic to foreigners with communication difficulties. I've played this is Spain too and the tutting begins much earlier.

A variation on this in Japan is to pretend not to speak English either. This will usually send the operator into a panic as he or she will usually try to speak some English if the foreigner doesn't understand. But if its Spanish then the situation has the potential for terrible muddle. I got caught out once, however, because someone in the queue could speak Spanish very well and my Spanish was clearly rusty and it gave the game away.

Another variant is to take a dictionary and search through for words that the operator has said to you. Again, this can lead to a lot of tutting and shifting of impatient feet.

A good game to try, particularly if you have been sent shopping on your own, is to try and get someone else to pack your goods for you. The aim is to look as inept as possible when packing. Often there are extra staff hanging around behind the tills, and one may take pity on you, you win if they do.
Another good one (certainly works in England but i fear other countries have trolleys with two fixed wheels) is to try and wedge your trolley fast in the narrow checkout lane. Hours of amusment can be had watching shop staff give you withering looks and attempting to move the trolley themselves.

The one about not understanding the checker happened to me for real once. I was in Germany, and my command of German is limited to Hello, Goodbye, Yes, No, Please, and Thank You. I bought a case of sodas, and the checker was trying to explain something important to me about something. I said, "English?" She looked at the women at the registers to either side of her in a panic, but neither of them spoke English either. Finally, she picked up her "panic phone," said something to someone on the other end, and handed the phone to me. I held it gingerly up to my ear and said, "Yes?" A voice at the other end said, "You have bought something in a can? If you want to redeem the can for the deposit, you must have your receipt." I said, "Oh, OK, danke (thank you)," and walked out of the store blushing red as a beet. It may be fun when it's a game, but it's *hugely* embarassing when it's for real.