Christmas cracker is a new concept I've learnt since making UK my home, a tradition that I have otherwise never encountered elsewhere. 

The idea is to put crackers on xmas trees until the xmas eve, and have two people pull on each side with the luckest one left with the juicy prices in the middle (often with a paper crown inside for the winner to show off). 

The tricky thing is to make the winning a random event. An early test shows the paper has a weakness on one side and therefore the one pulling on that side ALWAYS wins. Imagine the disappointment for the one that happened to be on the "wrong" side! I had to randomise the paper by shifting sides before tying up the string so that it will be truly a surprise as to who gets the prizes. Phew!