A few years ago, with some friends, I developed a way to play backgammon that is, to my knowledge, the most challenging, fun, and best learning experience. It can be played with two people, or you can play doubles as well.
Basically, we play each other on the computer, usually on Snowie, and we have the right to challenge every play and cube decision our opponent makes.
Here are the details as to how it works.
Decide in advance how much you want to play per point, but we generally play a 5 or 7 point match for 5 points, and every challenge is a point. Let's say my opponent rolls a 4-5 and makes his play. Instead of rolling or doubling, I can challenge his play. I must declare what play I think is better, and then we go to Snowie explorer, move it back to the previous play, hit 3-ply, and see who's play was better.
If the difference between the plays is .020 or less, we call it a tie. And we make the same bet on every cube (or no-cube) decision.
If you play with four people I suggest you play non-consulting on the plays, and have each player take a turn on each roll. If you have consulting, it will simply take too long to make a move. We also play non-consulting on the challenge. Only the player who has the next turn can challenge the previous play or cube decision.
Talk about a game of skill! You can win or lose money on every single play, and I guarantee you it will sharpen your game. Also, when you do make a mistake, I also guarantee you that you are much more likely to remember that error.
By the way, you can play this same game on GnuBG or Jellyfish with all the same rules and variations.
Many people ask me about these three most popular backgammon programs: Snowie, GnuBG, and Jellyfish. My stock answer is that they are all excellent, but I personally have found Snowie the easiest to use and understand, so I generally use Snowie for just about everything I need. Most of the top players in the world agree with me about Snowie, but they also believe there are advantages to using the other programs for rollouts and for certain kinds of advanced valuations.
One thing has become very clear to us all about these programs (we call them "bots"): they are excellent. They are not perfect, but in most cases they will play better than just about any human players. They are based purely on math. If Snowie prefers one play over another, it is because that play is the one that is going to net more total points (wins plus gammons plus backgammon vs. losses plus getting gammoned plus getting backgammoned) for the player making the play.
Not only do the bots tell you which play is best, it tells you by what percentage. For example, let's assume you get an opening roll of 3-1. Everyone knows that the best play is to make your 5 point (generally accepted as the most important point you can make early in the game). If you ask Snowie about this play, it will show you that making the 5 point is approximately 22% better than the next best play. This means that over the long run, you will win 22% more points by making the best play. Now, that's a huge percentage for just one play at the beginning of the game, so we can see how important it is to make the right play.
Often the differences are very small between the best play and the next best play, but the better you are, and the better your opponents are, the more important even these small differences become. In a typical game, a very good player might make 5 or 6 checker errors. Even if each one is only 2% worse, when you add them up he's given away a total of 10% of his equity (or chances to win). The top players in the world will often play an entire game with only one or two errors, and often those are very small.
My point is that the bots are extremely good and give us a lot of excellent information, and one of the best ways to learn is to play against the computer, or as I suggested, play on the computer and check your plays.
The Snowie Challenge game allows you the opportunity not only to play the game and have a friendly competition against another person, but also to check your skills on the computer to sharpen your game and learn.