Ah, the hard ones first, eh? Well, "Christmas Crackers" are decorative party favors. Each consists of a simple cardboard tube (typically about 1.5 inches in diameter and 6 inches long) that is wrapped in pretty Christmas-like paper. This wrapping protrudes about 3 inches from either end of the cylinder making the whole thing about a foot long.
The cardboard tube usually contains a paper party-hat/crown, a silly joke or riddle, a small gift or novelty item, and a special popping (cracking) device that makes a "bang". On Christmas day, in addition to knives, folks, spoons, napkins, and so forth, each place-setting at the dinner table also includes a Christmas cracker. The first thing everyone does when they sit down is to pick up their cracker, firmly grasp hold of one end, and offer the other end to someone else at the table. Both people pull hard, there's a loud "crack" and the contents of the cracker fly out of the tube and (usually) get lost under the dinner table.
After retrieving the contents from their various landing places, everyone then dons their silly paper hats (which must remain in place until the end of the meal), takes it in turn to read their joke or riddle to the throng, and – eventually – gives the novelty items to the kids. (If you are really rich, you can purchase incredibly expensive versions containing fine jewelry and suchlike.)
So how did this all start? Well, crackers have been a traditional part of British Christmas festivities since the Victorian Times. In the mid-1840's, a London pastry cook named Tom Smith visited Paris and observed the French holiday custom of wrapping sugared almonds and other sweets and candies in a twist of colored paper. From this humble starting point, Smith gradually evolved the pyrotechnic version we know and love to this day.
Of course this has nothing whatsoever to do with Programable Logic or Structured ASICs, but you never know when this sort of information will come in useful (in which case remember that you saw it first on www.pldesignline.com).