On an unimportant note, jokers are not included in poker, nor in almost any other game. It is my understanding that they exist to use as replacement cards in the case of a lost or damaged card (rather than having to throw out the deck.)
Jokers are actually used in occasional uncommonly played poker games (certain variants of 5 card draw). For the most part those games haven't been played much in public card rooms since 10-20 years ago but you can occasionally come across a game.
