So about poker:
First of all, there are different kinds and variations of poker. Personally, I like Stud and Five card draw, but there are others like Texas Hold'em, and Omaha. Because it's the easiest, I'll just try to explain Draw.
In all types of poker, there are two materials: playing cards, and poker chips. The cards are necessary, but you can use other things in place of cards, like coins (some people use pennies, nickels, dimes, and quarters to play) or even candies. When I play, I have a nice case of professional, heavy, ceramic champion-weighted poker chips. They're basically just round, semi-heavy tokens that are marked with different colors. Different games and people will set their values differently, but generally, they are just "chips" with colored marks, the values for each color being as follows:
White=1
Green=5
Red=10
Blue=20
Black=40
In a real game (like, in an old saloon or in a modern casino), you would buy the number of chips you wanted based on the values of each.
The dealer shuffles a deck of cards, and everyone puts in their initial bet (we call it a Rosy). This is usually just one chip, put in the middle of the table. It shows that you will be in the game and playing. By the way, the center of the table where the chips go will be called a "pot".
The dealer now deals out five cards to each player. Each player looks at their cards and determines what they will do. This is when the first round of betting takes place. This means that the player to the left of the dealer will put in however many chips he wants. If he didn't think that he has good cards it that he will lose, then he might only put in a white chip. But if he thinks he has good cards, he might bet a red chip. Or, if he really doesn't like his hand, he can fold, which is when a player puts puts down his cards and quits the game.
The play then continues to the next player. She may choose to fold as well, or she can see the other players. By seeing them, she will either bet the same amount that player one did, or she might bet even more. This way, the next player has to do the same thing. Once it gets back to the dealer, players can trade up to three of their cards for new ones that they hope will be better.
A second round of betting then takes place. It goes the same as before. If there are players that didn't fold, then they all reveal their hands. The player with the best cards then takes the pot and wind that round of play.
The hands of cards are ranked, to determine who has the best five cards.
Royal Flush: A, King, Queen, Jack, 10, all in the same suite. --This is the best possible hand, but it hardly ever happens to anybody. To get those exact five, all in the same suite, like hearts, is a true miracle.

The most common is that last one: high card. I mean, every time you have a high card, so it shouldn't really count. Saying that, I've won lots of chips just because I had a terrible hand of, like, a high of six. That's about the worst hand possible. Oh, and sorry I couldn't make that picture a bit smaller. It was just the best one I found for you on an internet search.
Hopefully you sort of get the idea. But, actually, I'm not sure how boring that was, but I kind of enjoyed it. Tell me if you have any questions at all about it. I'd be more than happy to tell you about it.