Movie-Based Games

• There are literally hundreds of games based on popular works of fiction, especially movies such as Harry Potter. Typically there is a message board and maybe a wiki filled with information about creating characters as well as the setting. People register at the site and then create their character. After registering, you introduce yourself and begin receiving email updates showing what other players are doing in the world. These are typically open-world role-playing games without a set storyline and concentrate on role playing. Some of these games go on for several years as players come and go.
  
  

Rules-Based Games

• There are many games based on popular rules mechanics, such as the d20 open gaming license (Dungeons and Dragons and its variants) that are thematically very similar to movie based games. These games, however, almost always have a games master (GM) to act as an adjudicator as well as to develop a plot or adventure. The GM will describe scenarios and events, and then players react to these events one at a time. Then the GM responds to their actions, then the players go again. This continues as players overcome each challenge and move from scenario to scenario. The GM also determines the success of actions based upon the rules system in place.
  
  

Strategy Games

• There are also classical strategy games (war simulations such as Chess or Chainmail). These are turn based and are a hybrid of rules based games, not always requiring a GM to operate. There is a set of rules that are fairly inflexible and tend to be much faster paced, often able to complete in several days.
  
  

What is right for you

• With so many different ways to play as well as tools available (email, forums, wikis, etc.) it really comes down to deciding the type of game you want to play as well as how much time you wish to invest in it. Rules-based games require you to play every turn, as do strategy games, but with the open worlds of fantasy games you can disappear for years and then come back to the community you remember. Find something that interests you and give it a try; since it is fairly anonymous, you can always leave and then come back, and no one will think any less of you. Make sure to let them know you are new, so players will come forward and help you get adjusted to how PBM games and the one you are playing specifically work.