Solitaire

So obviously Solitaire has been around for a while, right? Everyone and their dog has played this classic card game (well, maybe not the dog; he's more likely to play poker...).
In case you don't know (but how could you not!), here is how the game goes. You try and create 4 piles of cards going in ascending order (put the ace down first and go up towards the king, there is no joker here). The piles are divided by suit (hearts, diamonds, spades, and clubs).

The key element to this game is that there are seven piles of cards below, with cards that can only be revealed after you have managed to remove the card above. To move a card to a different pile, you have to place it onto another card that is not only the opposing color, but which is one rank higher than it. And all the while, you have the remainder of the deck to draw from (not all the cards are on the field).
Like the name suggests, this game is for solitary enjoyment. It is very much so a game for the individual. There are no teams, so opponents, no partners, only you. Of course, if you want, you can compete against the clock, but even then, the game is one-player. The only way solitaire can ever exist as a two player game are in its variations such as Speed (where you are trying to go faster than your opponent) and Seven Up (very vaguely related to Solitaire). I find it a shame that I have never found any other versions of solitaire anywhere (though some may argue that the numerous other computer card games on the internet all closely resemble the original Solitaire).
This game is a fun waste of time. There is no real goal to shoot for except to actually get all the cards into their respective piles. But even after that, there is nowhere to go afterwards, you just start over. The game can be addictive if you have the type of personality that enjoys card games like this. The fact that you can't always win makes it more addictive. But, for most people, you will most likely get bored of it after a couple of days. After that, you may occasionally click back to it, but the appeal of the game lessens and lessens the longer you have it. If fact, you're actually better off simply getting one of the many other available card games such as Tripeaks, Hearts, or Freecell.
So there you have it. Solitaire. It's fun but quickly loses its appeal.